Did you know that folding paper was so difficult!!!!!!
So imagine you are asked to fold a narrow piece of paper edge to edge. Do you understand the word edge? In this context? It's not the edge of a cliff! So the action starts and you lift up the edge nearest you and take it to the other edge (I'm assuming you do understand the word edge). Then what? Hold it there.....how to make it stay there? Oh, push down on the looped part of the paper. Done. Oh, no, it has sprung up. What to do? Actually, you need to push firmly along the very edge.....is that an edge too? Yes, right on the edge. And all the way along. Completely all the way along.
Right, got that.
And now, what about a wider piece of paper. Well, it gets trickier. You need to coordinate more fingers and different pressure.
And then, what about folding a piece of paper along a line. So you have a narrow piece of paper and you fold it over. Oo..oh. Can't see the line!! How do you do it? Well, the planning and coordination is quite fine. You need to fold it nearly over and then continue to peep under to see if it looks like the fold is going to. And then also look to see if the fold is straight. Oh boy! Tricky. You need to be able to visualise where the line is, even when you can't see it. OK. can you do this?