You can charge your attacks to slide these mammuts along the ground, and you will need to do so to solve some puzzles. One puzzle in particular makes you form them into the shape of a small L, and you will be able to tell where they should be placed by large tiles on the ground. It's actually pretty easy to get them all in to place, but what you should keep in mind are the angle you can hit them from. You have to do a charge shot, which is long range, and has wide hitboxes. Even if you can't get behind the mammuts, you can still shunt them forward by getting one block behind and to the side of the beast. From this point you can still hit them. You can also hit them from range, and one puzzle in particular will make you move to a different area entirely before charging a move from there and flying it across a gap at a mammut.