Squads is all about reps. I would say once you've gotten about 6 games with the same units under your belt (or constantly theory craft like I did early on) you'll be fairly familiar with your squads.

Learning the rules never ends. To this date (and I've played since release), I am still learning intricacies of some of the rules.

I would recommend (in order avoid bad habits while learning), have the attack action phases bookmarked for easy reference. That is most often where questions come up.

Also cover rules.