Congrats on YOUR new boat!
Left something electrical on? Been there done that...dead battery! Did that a couple of years ago and launched it with a friend on board. She could not get it started. So, we got a jump start from another boater. I went and bought some l o n g jumper cables for the boat per her recomendation.
I put the offending radio on a seperate power switch. See my 'Tool Box Stereo' posted in the photos section.
Doing the parking lot manuvers is a good idea. Just remember to swing wide on all of your turns.
Take your time learning the boat and how it manuvers and functions.
Safety courses are not required here in GA. But I took and passed the courses offered for SC, GA and TN. I can tell that some people don't have a clue about rules, so don't assume everyone has taken a course.
Post some photos of your boat and any projects, when you get a chance.