please help lol
That depends on lot of things.
Which OS is your computer? Did you download the version of the game that matches your OS?
Are you using the itch.io app or did you just download the .rar archive? If you are using the app, then I don't know and you should find a tutorial for the app.
If you have the archive, then you need to extract it using the latest version of WinRar or another compatible archive extracting utility. At some point in the last couple years there was a change to the archive format, which requires the use of newer versions of WinRar. Once extracted, the game is mostly a simple program and should start like other games.