This was the first cruise for ourselves, a professional couple in our 40's with preteen sons.
The boarding process was confusing, and Carnival would do well to provide a "know before you go" letter about the process. Much like an airport, but since you don't know what you are getting into, it was hard to plan. We were herded like cattle into a queuing line for going through the requisite metal detectors, then for our "sail and sign" boarding and room cards, then for the actual going up the gangplank. No pleasantries, no signs, nothing. This was to be an advanced warning for what appears to be the Carnival way of operating - efficient, but no smiles, no concessions, and lots of lines. That's fine for a factory or for a stockyard, but not for a cruise line. We allowed about an hour to get from the parking lot on board ship, and that was about what it took.
Once on board, we found our cabin without problem. Our luggage arrived well after we boarded - we boarded at 2:30, departed at 5:00, and it arrived while we were eating dinner, between 6:30-8:00 - which meant we could not have changed unless we had put our change of clothes in our carryons, which we fortunately did.