Type in fishtail bracelet turorial or paracord fishtail sling and click images or videos. Its basically a modified fishtail bracelet. That's some fine work though.
Looking at it it looks like there are six cords that make up the core, each wrap goes around two. As far as the blue strip, thats just gutted cord worked in as they weave. You can iron it under a tshirt to really get it flat if you want.
You might want to get some hemostats, your fingers will get tired weaving that and trying to keep it tight. You can clamp them on to hold your place while rest. You might want to invent a jig with some 2x4 and nails to keep your length right while you work, im sure this would help.
Let us know how it turns out!