All this is described very well in the Ascend manuals. Almost all Ascend documentation is done very good. We know, as a newcomer, you must start slowly, to get it. If you are brand new to all kind of routers, it takes some more time.
We have had some trouble too in 1996, when we did open the first huge Ascend "book" with over 500 pages (there 4 big books in the box), totally confusing us with a lot new terminologies and more. But that was in 1996. Now there is a lot more basic skill and knowledge about data communication in the field.
So check our PDF database for MAX manuals and start reading. The pictures and drawings will talk themselves. You will shortly find out, it easy reading and the index is very nice to find what you are looking for.