Thanks, all of these answers definitely help.
I think the main problem is that the documentation doesn't really give the "big picture" (or at least I can't find it) because it's sort of "assumed knowledge" by the people who already use the system - it's already intuitive to them. But to an outsider first coming in, it's hard to get a grasp on what he is looking at.
For instance when I opened the product for the first time, I didn't know if this was a demo website I was supposed to modify for myself, an administration tool to administer developers who would be working on the system, or some other thing. It in fact looks like all of these things. I guess you would tell me that it in fact IS all of these things?
1. So... assuming I just want to build a single website for a single entity, not the complicated hotel example you gave, the recommended approach is to take the ACME "main site" and customize it and change it around to make it my own?
2. For my own website I will need to extend the "Users" database table I found to also include other information such as address, phone number, etc. Is the recommended approach to add another table with that information, and use a foreign key from the Users table? Easy enough, but in adding and removing users, I need some way to extend those already-existing functions. I believe I read that there were callbacks and such that could be used for this?
I really appreciate the help here. This community seems very friendly. This product is certainly powerful - probably the most advanced I've seen for this sort of thing. It's just a little rough around the edges as far as the documentation and what not. If I get to be good enough using this thing, I'll chip in with whatever help I can.