My only real challenge was using the snap fastener kit. I was really terrible at getting the snaps in correctly. haha
I would suggest making yourself up a 'jig' that's what I've done with items I make often, like tea wallets....make a piece of cardboard the same size as your fabric, then mark where you want the snap to go.
Make a hole in the cardboard at that position, and use that as a template (jig) so that all the snaps are in the same position.
I used to use a small wooden chopping board to do my snaps on. Patience and not rushing helps. Push the pronged bit through whichever way it has to go, with any marking in the centre of the hole. Put the corresponding piece on and use one of the tools to gently hammer them together.
A couple of pointers I found out the hard way were:
1. The tool like the one you have aren't easy to use, I have a round metal one with a small lug out one flat side of it....they're so much easier to use.
2. Use extra interfacing in the snap area section for stability so it doesn't pull out of the fabric.
3. Find yourself an old drill bit or something similar in size to the hole in the female half of the snap....when you're done inserting it, push the drill bit into the hole and gently hammer it in a little way, pull it out, rotate the snap (and fabric) slightly and repeat...this opens the hole a bit and also helps it pull out. If you use too big a bit it will make the hole too big, so it's a case of trial and error.
4. If you're using fancy snaps that have pretty or metal raised tops on the outer side, then put a towel over the chopping board or hard surface, to protect the gem/metal finish.
Good Luck, and if you need any further instructions, let me know and I'll try and help.