You can compile .NET Standard libraries, run tests and run an Avalonia application on Windows, Linux and macOS operating systems. Make sure you have latest [.NET Core SDK](https://dot.net/) installed.
You can compile Universal Windows Platform Camelotia app only on latest Windows 10. Make sure you have latest [Microsoft Visual Studio](https://visualstudio.microsoft.com/) installed. Make sure the "Universal Application Development" section is checked in [Visual Studio Installer](https://visualstudio.microsoft.com/ru/vs/).
To compile the Xamarin Forms Android application, you need to install appropriate Android SDK v8.1. This can be achieved by using [Visual Studio Installer](https://visualstudio.microsoft.com/ru/vs/) and selecting "Mobile Development" section there.
File system providers are located at `./Camelotia.Services/Providers/`. To add a custom file system provider, you need to create a separate class and implement the [IProvider](https://github.com/worldbeater/Camelotia/blob/master/Camelotia.Services/Interfaces/IProvider.cs) interface. Then, add your provider to composition root for each platform that should support it.