...To use FlaUI, you need to reference the appropriate assemblies. So you should decide, if you want to use UIA2 or UIA3 and install the appropriate library from NuGet. You can of course always download the source and compile it yourself. The entry point is usually an application or the desktop so you get an automation element (like a the main window of the application). On this, you can then search sub-elements and interact with them.
Framework for making Windows applications that are one .exe file in AutoHotKey_L,C++,C#, VB.NET,Java,Groovy,Common Lisp,Nemerle,Ruby,Python,PHP,Lua,Tcl,Perl,Jint,S#,WSH VBScript,HTML/JavaScript/CSS,COM, PowerShell without compiling . For .NET 4.