Extract the archive somewhere (eg: in a folder on your desktop)
Turn off your antivirus (some antiviruses might cause some issues)
How to play on Redstar
Run Novah - RedstarOSU.exeas administrator
Click on Switch to Redstar
If there are some dialogs about intalling the HTTPs certificate, always click on Ok/Yes. The HTTPs certificate is needed to properly connect to redstar
Make sure that the switcher says You are connected to Redstar
Open osu! and login with your Redstar account
Enjoy
NOTE: If you can’t install the certificate through the automatic procedure, follow these instructions to install it manually.
How to play on official osu! again
Make sure osu! is closed
Open the switcher and click Switch to osu!
Make sure the switcher says You are connected to osu!
Open osu! and login with your osu! account
NOTE: If you want to connect to osu!’s website and you see redstar’s website or an error, even if the switcher claims you’re connected to osu!, empty your browser cache and restart your browser.