Membership install with commomn tables

If Assign a category to all things in a particular level, Does that mean they'll be hierarchical. i.e.

airplanes
big airplanes.
Small airplanes

Will, both big and small airplanes be protected, as well as anything I add in the future?

Trying to set up Network to my Membership install. So that sub-directories can use one common login. (Global Tables)

On page 77 of the Membership Manuel it says set certain variables in membershipconfig.php. File is not located at the stated location. ?

Replaced, moved, put them in the wp-config.php file,or what?

And where will the tables come from ?

Thanks
Ron