As a beginner, how do I know when to fold and when to keep playing my hand?

Your question is way too general. Do you mean preflop? Even then, it depends. What position are you? What actions have other players taken?.

To simplify, there are preflop starting charts. Look at these and learn them. I would suggest playing at least somewhat tighter than they suggest, though. They are based on being able to play at least above-beginner level postflop. As a beginner you will obviously mess up postflop. Playing tighter than the charts will mean you are playing mostly strong hands that are easier to play postflop.

This is common advice on here but I don't really like it especially for a beginner. There are lots of preflop charts and many aren't great. Many of the preflop charts that come with equilab for example are already very tight so playing tighter than those would be bleeding blinds. Or do you specifically mean GTO preflop charts?

As for when to fold and when to keep playing well that is about half the skill of poker so it's not something you can learn fast. A good place to start is learning when you should mathematically fold/ continue by understanding pot odds and required equity..

I was thinking of the GTO charts and eliminating the near zero EV parts of the starting hand range for a beginner. Those hands require better postflop play than what a beginner can hope for to turn a profit.

As a beginner learn to play as a nit and lose the least amount while getting the most learning experience.

Fold every hand until you get a hand that you know you shouldn't fold - then raise. Easy game.

GTO WIZARD will tell you in the free version which hands to play in some situations. Google why AA is a raise 2x preflop 50BB deep. Why 45o is a fold 30BB deep in a MTT.
repeat the question and ask Google why AA is a call preflop 50BB deep.

that's some of the info u will get. click on the pages below that. more info. quicker than getting a response here.