You do not need a rack to train legs. Squats, lunges, glute bridges and wall sits cover the quads, glutes and hamstrings, and bodyweight becomes genuinely hard once you control tempo and range.
Start from the air squat
Set your feet shoulder width apart with the toes slightly out. Sit down between your hips rather than over your knees until your thighs reach at least parallel, deeper if your back stays neutral. Keep the whole foot glued to the floor.
Take three seconds to descend and drive up with intent. If your heels lift, widen the stance a touch and slow the rep down before anything else. Ten smooth reps with a three-second descent are worth more than thirty fast ones, so earn the rep count after you own the depth.
Add lunges for balance and single-leg strength
Step back into a reverse lunge, which is kind to the knees and easier to balance, dropping until both knees are bent about 90 degrees. Push the floor away to stand and alternate legs.
Keep the front shin close to vertical and the torso tall. If you wobble, hold a door frame or slow the tempo before you shorten the range. Start with bodyweight only, and add a backpack once every rep looks the same on both legs.
Train the backside with glute bridges
Lie on your back with your heels close to your glutes. Drive through the heels, squeeze the glutes hard at the top for two seconds, then lower with control. The lift comes from the hips, not from arching the lower back.
Keep the ribs down and the chin tucked. If your hamstrings cramp, that is normal at first and it eases with practice. When two-leg bridges get easy, move to single-leg: same rules, half the base, twice the burn.
Make bodyweight work hard again
Add a three-second pause at the hardest point, stretch the descent to five seconds, or use 1.5 reps: all the way down, halfway up, down again, then up. Sets of twenty to thirty reps become legitimate once every rep is slow and deep.
Pick one hardness knob per session, not all of them at once; slow and deep beats fast and sloppy. Finish with a wall sit: slide down until your thighs are parallel and hold for 40 to 60 seconds. It stings, and it works.
Put it into a repeatable session
Run three or four rounds of air squats, lunges and glute bridges, 10 to 15 reps each, resting about a minute between rounds. Do this twice a week and log it in Bulky.
Note which variation you used, so next time you know exactly what to repeat. When the session stops feeling hard, swap in the harder variations above. Progression at home follows the same order as the gym: more control, more range, more reps.