JD of TyingItAllTogether, just put up a YouTube video on 'How to Make a (Paracord) River Bar Bracelet'. I gave it a try this morning and JD's video was easy to follow.
I started with two 6 foot lengths of paracord, as was mentioned in the video's comments, and ended up actually using about 9 feet in the finished bracelet. I made the finished length at about 10 inches, which made for a loose fit on my 8.5 inch wrist. I think that a half inch larger than wrist size would probably make for a snug fit, so making it somewhere between 0.5 and 1.5 inches longer than your wrist measurement will make for a comfortable fit. You can wrap it around your wrist to check the length as you tie it, so you'll know right about where you want to stop tying.
The knot patterns are different on each side, but I prefer the directional pattern facing out, just like JD shows it in the video. YMMV
I made this one with the overhand knot and loop closure, as in the video, but a lanyard knot would also work, and I believe I could probably make it work with a side release buckle too(photo added).