All valid points. One more tip that is often underrated in beginner’s courses is a proper trim. Many new divers are frustrated by their gas consumption, but move more like a seahorse than a fish. A nice horizontal position saves a whole lot of gas.
Whatever happens, don’t panic. Stick to what depth your comfortable with. Don’t be fooled into a false sense of security by your Dive master. Find a good DM. There’s some very average ones around.
Anyone else notice the fact that Mark speaks in whole sentences without the one sentence being compiled from like 10+ cut scenes??? Major props for that and excellent content, very informative!!!