the short answer
The hip thrust is a glute-focused lift where you rest your upper back on a bench, load a barbell across your hips, and drive the hips up until your torso and thighs form a flat line, then lower under control. It loads the glutes hardest right where they are strongest - at lockout. The single most important cue is to finish with a glute squeeze at a level lockout, not by arching the lower back to push higher.
This article is general technique education for coaches and clients, not medical or rehab advice - form is individual, and a qualified coach watching the movement and giving a form check is the gold standard. Clients with pain or a relevant history should clear it with a qualified professional first.