I can't build the project

[ArneDoering]

I did not find any build instructions, so I just went with the dotnet build on the command line. This is what I got:

─[arne@arne-dell-xps:~/p/DearImGui]─[13:54:34]─[G:develop =]
╰─>$ dotnet build
/usr/share/dotnet/sdk/9.0.110/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.EolTargetFrameworks.targets(32,5): warning NETSDK1138: The target framework 'net6.0' is out of support and will not receive security updates in the future. Please refer to https://aka.ms/dotnet-core-support for more information about the support policy.
/usr/share/dotnet/sdk/9.0.110/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.EolTargetFrameworks.targets(32,5): warning NETSDK1138: The target framework 'net6.0' is out of support and will not receive security updates in the future. Please refer to https://aka.ms/dotnet-core-support for more information about the support policy.
/usr/share/dotnet/sdk/9.0.110/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.EolTargetFrameworks.targets(32,5): warning NETSDK1138: The target framework 'net6.0' is out of support and will not receive security updates in the future. Please refer to https://aka.ms/dotnet-core-support for more information about the support policy.
Restore succeeded with 2 warning(s) in 0,4s
    /home/arne/proj/DearImGui/imgui/imgui.vcxproj : warning NU1503: Skipping restore for project '/home/arne/proj/DearImGui/imgui/imgui.vcxproj'. The project file may be invalid or missing targets required for restore.
    /home/arne/proj/DearImGui/implot/implot.vcxproj : warning NU1503: Skipping restore for project '/home/arne/proj/DearImGui/implot/implot.vcxproj'. The project file may be invalid or missing targets required for restore.
  imgui failed with 1 error(s) (0,0s)
    /home/arne/proj/DearImGui/imgui/imgui.vcxproj(28,3): error MSB4278: The imported file "$(VCTargetsPath)/Microsoft.Cpp.Default.props" does not exist and appears to be part of a Visual Studio component. This file may require MSBuild.exe in order to be imported successfully, and so may fail to build in the dotnet CLI. 
  implot failed with 1 error(s) (0,0s)
    /home/arne/proj/DearImGui/implot/implot.vcxproj(28,3): error MSB4278: The imported file "$(VCTargetsPath)/Microsoft.Cpp.Default.props" does not exist and appears to be part of a Visual Studio component. This file may require MSBuild.exe in order to be imported successfully, and so may fail to build in the dotnet CLI. 
  DearImPlot.Generator failed with 1 error(s) (0,0s)
    /home/arne/proj/DearImGui/DearImPlot.Generator/DearImPlot.Generator.csproj(35,2): error MSB4278: The imported file "$(MSBuildExtensionsPath)/Microsoft/VisualStudio/v$(VisualStudioVersion)/TextTemplating/Microsoft.TextTemplating.targets" does not exist and appears to be part of a Visual Studio component. This file may require MSBuild.exe in order to be imported successfully, and so may fail to build in the dotnet CLI. 
  DearGenerator failed with 1 error(s) (0,0s)
    /home/arne/proj/DearImGui/DearGenerator/DearGenerator.csproj(58,2): error MSB4278: The imported file "$(MSBuildExtensionsPath)/Microsoft/VisualStudio/v$(VisualStudioVersion)/TextTemplating/Microsoft.TextTemplating.targets" does not exist and appears to be part of a Visual Studio component. This file may require MSBuild.exe in order to be imported successfully, and so may fail to build in the dotnet CLI. 
  DearGenerator failed with 1 error(s) (0,0s)
    /home/arne/proj/DearImGui/DearGenerator/DearGenerator.csproj(58,2): error MSB4278: The imported file "$(MSBuildExtensionsPath)/Microsoft/VisualStudio/v$(VisualStudioVersion)/TextTemplating/Microsoft.TextTemplating.targets" does not exist and appears to be part of a Visual Studio component. This file may require MSBuild.exe in order to be imported successfully, and so may fail to build in the dotnet CLI. 
  DearImGui.Generator failed with 1 warning(s) (0,0s)
    /usr/share/dotnet/sdk/9.0.110/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.EolTargetFrameworks.targets(32,5): warning NETSDK1138: The target framework 'net6.0' is out of support and will not receive security updates in the future. Please refer to https://aka.ms/dotnet-core-support for more information about the support policy.
  DearImGui failed with 4 error(s) and 2 warning(s) (0,1s)
    /home/arne/.nuget/packages/microsoft.build.tasks.git/1.1.1/build/Microsoft.Build.Tasks.Git.targets(25,5): warning : Could not find file '/home/arne/proj/DearImGui/imgui/imgui/.git'. The source code won't be available via Source Link.
    /home/arne/.nuget/packages/microsoft.build.tasks.git/1.1.1/build/Microsoft.Build.Tasks.Git.targets(25,5): warning : Could not find file '/home/arne/proj/DearImGui/implot/implot/.git'. The source code won't be available via Source Link.
    /usr/share/dotnet/sdk/9.0.110/Microsoft.Common.CurrentVersion.targets(5322,5): error MSB3030: Could not copy the file "/home/arne/proj/DearImGui/build/x64/Debug/imgui.dll" because it was not found.
    /usr/share/dotnet/sdk/9.0.110/Microsoft.Common.CurrentVersion.targets(5322,5): error MSB3030: Could not copy the file "/home/arne/proj/DearImGui/build/x86/Debug/imgui.pdb" because it was not found.
    /usr/share/dotnet/sdk/9.0.110/Microsoft.Common.CurrentVersion.targets(5322,5): error MSB3030: Could not copy the file "/home/arne/proj/DearImGui/build/x64/Debug/imgui.pdb" because it was not found.
    /usr/share/dotnet/sdk/9.0.110/Microsoft.Common.CurrentVersion.targets(5322,5): error MSB3030: Could not copy the file "/home/arne/proj/DearImGui/build/x86/Debug/imgui.dll" because it was not found.
  SampleApplication.OpenTK failed with 1 warning(s) (0,0s)
    /usr/share/dotnet/sdk/9.0.110/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.EolTargetFrameworks.targets(32,5): warning NETSDK1138: The target framework 'net6.0' is out of support and will not receive security updates in the future. Please refer to https://aka.ms/dotnet-core-support for more information about the support policy.

Build failed with 9 error(s) and 9 warning(s) in 0,9s
┬─[arne@arne-dell-xps:~/p/DearImGui]─[13:54:38]─[G:develop =]
╰─>$ cd SampleApplication.OpenTK/
┬─[arne@arne-dell-xps:~/p/D/SampleApplication.OpenTK]─[13:54:45]─[G:develop =]
╰─>$ dotnet build
/usr/share/dotnet/sdk/9.0.110/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.EolTargetFrameworks.targets(32,5): warning NETSDK1138: The target framework 'net6.0' is out of support and will not receive security updates in the future. Please refer to https://aka.ms/dotnet-core-support for more information about the support policy.
Restore succeeded with 1 warning(s) in 0,4s
    /usr/share/dotnet/sdk/9.0.110/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.EolTargetFrameworks.targets(32,5): warning NETSDK1138: The target framework 'net6.0' is out of support and will not receive security updates in the future. Please refer to https://aka.ms/dotnet-core-support for more information about the support policy.
  DearImGui failed with 4 error(s) and 2 warning(s) (0,0s)
    /home/arne/.nuget/packages/microsoft.build.tasks.git/1.1.1/build/Microsoft.Build.Tasks.Git.targets(25,5): warning : Could not find file '/home/arne/proj/DearImGui/imgui/imgui/.git'. The source code won't be available via Source Link.
    /home/arne/.nuget/packages/microsoft.build.tasks.git/1.1.1/build/Microsoft.Build.Tasks.Git.targets(25,5): warning : Could not find file '/home/arne/proj/DearImGui/implot/implot/.git'. The source code won't be available via Source Link.
    /usr/share/dotnet/sdk/9.0.110/Microsoft.Common.CurrentVersion.targets(5322,5): error MSB3030: Could not copy the file "/home/arne/proj/DearImGui/build/x64/Debug/imgui.dll" because it was not found.
    /usr/share/dotnet/sdk/9.0.110/Microsoft.Common.CurrentVersion.targets(5322,5): error MSB3030: Could not copy the file "/home/arne/proj/DearImGui/build/x64/Debug/imgui.pdb" because it was not found.
    /usr/share/dotnet/sdk/9.0.110/Microsoft.Common.CurrentVersion.targets(5322,5): error MSB3030: Could not copy the file "/home/arne/proj/DearImGui/build/x86/Debug/imgui.pdb" because it was not found.
    /usr/share/dotnet/sdk/9.0.110/Microsoft.Common.CurrentVersion.targets(5322,5): error MSB3030: Could not copy the file "/home/arne/proj/DearImGui/build/x86/Debug/imgui.dll" because it was not found.
  SampleApplication.OpenTK failed with 1 warning(s) (0,0s)
    /usr/share/dotnet/sdk/9.0.110/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.EolTargetFrameworks.targets(32,5): warning NETSDK1138: The target framework 'net6.0' is out of support and will not receive security updates in the future. Please refer to https://aka.ms/dotnet-core-support for more information about the support policy.

Build failed with 4 error(s) and 5 warning(s) in 0,8s
┬─[arne@arne-dell-xps:~/p/D/SampleApplication.OpenTK]─[13:54:48]─[G:develop =]
╰─>$ 

I could not find any other build instructions or how to use instructions.