An awl is a tool that allows you to sew through very thick materials. It takes a bit of practice to master, but once you have it down you'll be ready to repair boots, webbing, and packs on the fly.
Stab the threaded needle of the awl through all the layers of fabric you are sewing.
Thick material is very hard to puncture. Be careful not to puncture yourself in the process.
If you are having difficulty puncturing the material, you can use a vice to hold the material in place, or place something on the backside of the material to puncture into. A rubber eraser works great.
Continue reinserting the awl, creating a loop of thread from the eye of the needle, threading the short, free end, and removing the awl to create your stitches.
While you are getting the hang of it, refer back to steps 6-9 of this guide.