I usually use the right-click and drag-mouse formation trick to get them to line up., i.e. select your units, right click on the map and drag the mouse. You'll see a line of pink dotted squares and stuff representing your unit formation after they get there. They'll start moving after you release the right mouse button.

Or align my line of sight in the direction that I want my troops facing and then move them.

I am sure there are easier methods, but I am not the kind that follows or pays attention to many tutorial tips.

Hope this helps.