Just playing around with it, I'm new to Army Builder.
But you can set the "rules" before hand. Faction (or any), max points (or unlimited), era (or any), rules level (intro/standard/advanced/experimental), advanced options (extrema range, alternate munitions, etc), and how to select skills (manual, true random, random by experience, etc).
Then you have a list of all units that fit your rules to select from.
The roster is shown below, with the total points (and your maximum).
The units in the roster can be grouped in to Lances/Stars/Level IIs, and you'll get subtotals of their PVs.
As you add each unit, it will be in red until you select a skill level.
When printing the cards, the images are automatically downloaded for the cards. (And there's an option to manually select a different image if you don't like the one the MUL uses...can't imagine why you might want to do that..).
Or you can print a roster that shows the rules you selected, PVs, AS stats, total cbill cost.
It's pretty easy to use, I didn't read the manual or anything :).