You try not to park on hills haha. But the concept is the same you just get better/quicker at doing it. When you’re letting off the clutch, the engine is connected to the wheels. Its enough to not need the brakes so you give it a bit more gas to get over the resistance of trying to go up a hill versus flat ground.

But some manuals will “hold” the brakes for a few seconds after you let off the brake pedal.

Also, everyone who drives manual stalls. You just laugh at how dumb you are and try again.