Okay, I dunno about AfterStep, I tend to use KDE or GNOME for my window manager... I have used AfterStep, and didn't find it super-hard to install or use... but it's been quite a while.
As to "getting access to everything" you MUST be "root user" on your system (Login root and whatever the appropriate password for that user is).
Caveat: Do not "make a habit" of signing in anywhere as root for anything other than administrative purposes (installing software systemwide, fixing problems with users, compiling code if you choose to do that and installing what you compile)... A good "rule of thumb" is, "anything you can do as some other user do do as some other user." For example, I do my best never to surf the web as root (I try not to log in to my graphical user interface as root at all if I can avoid it... I may be being overprotective, but, better safe than sorry, besides, most graphical programs for doing things like user management will ask for the root password if you're not logged in as root.
As far is AfterStep is concerned... what seems to be the problem?