The serve, done right
Padel serve rules are stricter than the rest of the game, so learn them first. You stand behind the service line, bounce the ball once, and hit it underhand at or below waist height into the diagonal box. The serve has to clear the net and land in the box without touching the side wall first, and you get two attempts, same as tennis. If it clips the net and still lands in, you replay it as a let. It sounds fussy, but after a few serves it becomes automatic.
Scoring you already know
The padel scoring rules come straight from tennis, so most people never need them explained twice. You count 15, 30, 40, then game, with deuce and advantage when a game is level. Six games wins a set and matches are usually best of three. One quirk worth knowing is the golden point, a single sudden-death point played at deuce instead of advantages. It is one of the few padel rules that changes from club to club, so check the format before you start.
Walls, lets and what is out
The walls are the part of padel that surprises tennis players most. A ball off the back or side glass is still live, so you turn and play it after the rebound. What you cannot do is let it bounce twice or hit the metal fencing on the full before it bounces. The ball is only out when it leaves the court over the glass or strikes the fencing before landing. These are the rules that settle most close calls, and they are simpler than they sound.