You have to right-click on this --

-- and pick "Customize" and then you can add different icons to whichever part of the toolbar you want. I added "New Layer" and "Resize" and some other things to my toolbar that I use most often. You also mentioned that you wanted to put the
Animation Shop icon on your toolbar and this is how you would do it. Here's a better screen, if my little graphic above doesn't ring a bell.