Always work out at your own level. If a standard squat is too challenging for you, or you can’t get a decent number of reps that way, use one of the intermediate levels (they go up in difficulty from 1 to 3). It’s OK to stretch yourself, but there are no bonus points for hurting yourself.
Stand comfortably with your feet slightly apart and facing outwards, then squat down. Keep your core muscles engaged.
Intermediate Level 1
Put your back against a wall or pole. Do the squats with your back sliding along the wall.
Intermediate Level 2
Stand facing a pole or doorpost. Hold onto it, then do your squats.
Intermediate Level 3
Place a bench behind you. On each squat, touch the bench before you go back up.