Working the thighs and the bum is about keeping it simple
Don’t do every exercise just do a few, but do them well.
Try doing bodyweight squats. progress to weighted squats
These are often performed incorrectly / ineffectively, too quickly.
If you can REALLY feel the muscles of your quads and glutes contracting then you’re doing it right.
The squat exercise works the quads and glutes as the prime movers.
The exercise is often done too fast and incorrectly; People often balance all of their body weight in their toes, their knees track too far forwards, and their glutes are higher than knees. Sometimes The upper back rounds and they don’t go down very low.
This position puts a lot of stress on the knee joint, people often do this because they are unaware of correct form and technique - this can mean the difference between an effective leg workout and a waste of time.
Practice a squat now, .... Put your feet shoulder width apart, toes can point out by a few degrees if it’s more comfortable.