The Playback speed is way too fast

I'm sure this is already a pretty common bug among users, but the playback tempo is way faster than it should be, since I am currently rewriting a song for the first time, and every time I want to hear what I have written, the playback speed is approximatively thrice the speed I want it to be. I've looked online for answers, but the only answer people seemed to give was to change your hz input, which I don't know how to do. Could anyone please help?