Hi Iuri,
I feel your pain, OpenACS is not easy to pick up for beginners. I think you probably solved 95% of the problem - one part I think you're probably missing is the actual Insert and Update statements. The part that always gets me (STILL!) is the xql files - sometimes you'll see 2 very similar queries, one in the .tcl and the other in the .xql. Usually I change the wrong file, and then spend 10 minutes swearing because my query is not working. 
It's all part of the learning curve of using a powerful piece of software. You're in "Black Belt" territory now. 
Never feel afraid to ask questions here on the forum - I know sometimes they are quiet, but there are plenty of people watching.
best wishes
Brian