Creative Ropecraft' by Stuart Grainger. It has great drawings of knots to follow and helped me with the braid for the belt.
I made this paracord belt with black and green cord, using a 6 strand flat braid and a buckle off an old leather belt. It's a bit narrow for a belt at around 3/4" wide, but it still works. I need to get some belt end tips, like these, that clamp down on the end strands, as my temporary sewing/melt of the ends was functional, but just too messy for my liking, so I didn't even take a photo of it.
I used three long cords looped onto the buckle at their centers. I made the belt extra long(around 60"), as a another way to carry extra cord, but I'm not sure how much paracord I actually used because this was a first attempt at this method. I started with about 100 feet of paracord cut into three equal lengths, but that turned out to be way too much. I'll have to measure the leftover strands I cut off to figure the actual amount I used.
The braid is done by taking the outer right strand and going over one then under one towards the center of the cords, then taking the left outer strand and going over one, under one, over one to the center. You then just repeat that pattern with the right outer, then left outer cords, not over tightening, but keeping uniform tension on the cords as you go so it looks even when finished.