No equipment. No excuses about equipment.
Bodyweight.
Every movement here needs nothing but the floor. Each one lists what it trains, how to do it well, and the mistake people actually make. Point at a muscle to narrow it down.
0 exercises for lower back
Nothing in the catalogue trains Lower back without equipment. Show everything.
These are cues from a reviewed catalogue, not personal instruction. Train within your own limits and stop anything that hurts.