What can I expect to happen?

I've had fixed braces for several months now, and i'm finally due to have my two (yes I only have two, weird haha) wisdom teeth removed, and i'm having a small polyp removed from the inside of my cheek, as it does get caught in the brace and be really quite painful. Since i'm having all of this done at the same time, i'm going to have it done under a general anaesthetic. I've never had anything like this done before, so naturally i'm quite nervous. Can anyone explain to me what I should expect, if I can eat the day of the procedure, what should I do after (i'm having this done March 23rd at 3.30pm)? No-one from the Orthodontic Department has actually told me what to do/expect, so i'm relying on you guys for now! <3