I also donated and only recently I started to "play" with it.
I confess, I also find it confusing. ABM is huge and within its samples, there is probably a wealth of information to help you but it can indeed be overwhelming.
Personally, I think it's easier to start with the smaller apps included in the download or simply using Erel's webapp samples for B4J here in the forum in order to get familiar with the concept and then gradually move over to ABM. This is what I am doing currently.
I also wish and think ABM would benefit from smaller tutorials (let us call them projects) to program smaller sites showing different arguments such as connecting to a DB backend, showing data in a grid and other common tasks and then I think the demo-app will make more sense for us beginners.