(temporary ui, subject to change. Wine not shown here with new UI)
Download the repository by clicking here and open with Visual Studio (make sure you have .NET Desktop Development), then once its all loaded click 'Build' and then 'Build Solution'
To access the built application, go to wherever you have the downloaded project and go to 'PheonixClient/bin/debug/net5.0-windows/'
To make this functional and not break upon launch you should download the 'test release' here and then replace the files inside there with the ones you have made
After building the project (I dont know how you even do that on linux so you might have to make a windows virtual machine and then transfer the files) you should install wine (if you dont know how, search up on google 'install wine on (your linux distribution)' and follow those instructions and continue to the next step, then download .net runtime from here and then open up your terminal and type in 'wine dotnet-runtime-5.0.7-win-x64.exe' and run that, follow install instructions until it is finished and then go to where PheonixClient is built to and open the terminal in that folder and run 'wine PheonixClient.exe' then it should open up just like it would on windows.
I have no idea why you would download this on linux since it doesnt download anything that could make games run on wine too, so i could get someone to help with that