grab the sources from github by:
git clone --recurse-submodules https://github.com/thesilvercraft/SilverAudioPlayer.git
And compile it yourself (that's why open source is good)
dotnet build
Before compiling it yourself consider editing SilverAudioPlayer.Avalonia.csproj
if you like unstable gui build apps try launching GUIBuild.bat or GUIBuild.sh