RPA Extract - Just drag and drop the rpa files onto the executable.
un.rpy - copy it to the folder where your rpyc files are at once you get them from RPA Extract and then run the game. It should decompile the files and give the .rpy files. MAKE SURE TO DELETE THE "un.rpyc" FILE FROM THE "game" FOLDER BEFORE BUILDING YOUR GAME OR DDLC MOD