When pasting in atloader.exe %LocalAppData%\osu!\osu!.exe or start atloader.exe %LocalAppData%\osu!\osu!.exe in shell or cmd prompt, you might have experienced an error message. I have found a fix:
Paste your bitness version in the folder in osu! folder.
Go to CMD or Shell, type start ,space, then drag atloader.exe into cmd or Shell. Then add another space and drag osu!.exe into cmd or shell. Click run and viola! I am currently in the process of setting it up but if I get it to work I will update this as soon as I can.