1.One legged squats. You put one leg on a bed or chair behind you, so that just the toes are propped on it. You squat, making sure your knee doesnt go beyond your toes if you would to drop a straight imaginary lien from your knee to your toes, kinda like a regular squat, really, focus on sitting back, rather than ot falling over
2. Pistols: looks like a one legged squat but one leg i straight in front of you. Hard work. Start from one and work your way up.
3. Plies: squat like a ballerina, feet pointing out, wide stance. Knees point to toes, keep back straight.
You can do regular squats and plies with a swiss ball on a wall behind you. That teaches you good form in the beginnig if you dont feel confident without hoding on to something.
4. TRy walking lunges, too.
That should keep you busy for a while.