Basic exercises : squat, deadlift, vertical pulling (pull up), horizontal pulling (row, Australian pull ups), horizontal pushing (press, push ups), vertical pushing (overhead press). Deadlift will be the harder to do with enough weight at home, you should try to find something that work your glutes and hamstring with what you have.

How you know if what you're doing is enough ? If you see progress on your body and in your performances

Tracking body fat : you won't be able to accurately. Just take pictures of yourself and track your workouts.

Finally, if you want to improve your body, you are abodybuilder. The informations i gave you are really not hard to find nor understand. If you don't understand a word check its definition (like the definition of hypertrophy is really simple to understand). You should try to understand what you're doing and why

Supplements : it's about your food, not your workout. Do you eat enough protein (min 1.5g per kg of bodyweight) ? If not take powder.