Thats because that thing that goes BEEP is a mind eraser and as all of us have done and will do is to learn the rule book 3 seconds at a time.
Glad to hear you enjoyed your first match. Stay with it the first one is always the toughest. Have fun with it, shoot straight and fast, and ALWAYS BE SAFE.
Holster your weapon command? There's no such command in IDPA,
Not in so many words, page 11 of the IDPA official rule book states after "hammer down, holster, and range is safe".
As the glossary states," HOLSTER:Command given to the shooter to put the weapon back in the holster"