This is a simple 15 hook darning loom.  It goes together with 4 M2 bolts. You need to bend 15 standard paperclips to make the hooks and clip off the excess.  

The bending jig is there to help you be more consistent in the bending.  You should bend them all starting from the hook end so that you repeatably get the same hook length. I varied my method and bit and I ended up with a few hooks that were not the same length and it makes it a bit harder to use in practice.

There are lots of darning loom how to videos on youtube. They all make it look easy…  If you see my example you know I need practice. I probably should have started with a less stretchy sock.