There is a guide somewhere, I can't remember where I saw it but there is one on the site.
If you're planning on making a skin from scratch it's going to be a awful amount of work, and could take 3-4+ months to finish, maybe even longer so you'd need to put the time in, providing you can understand the guide as it's very complicated.
I'd recommend you wait for a few skins to come out, then just edit them for now to build up some basic skills then maybe do one from scratch if that's what you want to do.