In the early stages of exercise rehabilitation, the current evidence indicates that hip focused exercises may be more effective than knee focused exercises. However, in the longer term, combining hip and knee exercises is likely to improve your outcomes.
As squatting is a knee base exercise, we suggest you start with the first 3 exercises (hip and core) on this site in the initial 2-3 weeks, especially if your knee is still quite painful. Once your pain has settled a little and you are making progress with the first 3 exercises, then gradually introduce this 4th exercise, being guided by your pain response.
Single leg squats