I've been asked for some additional photos of the hay baler. (Please excuse the pile of Stuff in the background.)
Instead of the rod where they attach the "eye" of the twine, ours has 2 small nails on the back of the baler for the same purpose. (Click on the photo to make it larger, then look for the nail. It's about 6" down.)
Also, there are two screw-in eyes (as in hook and eye) on the bottom of ours - the twine is threaded between the wooden rib and the eye (not through the eye) to hold it in place as we put in the hay. It then pops out when the finished bale is removed.
We found that the heaviest baling twine works the best; we had trouble with lighter twine breaking. We've also used baling wire with success.
I hope these are helpful. My hubby agrees that the plans online are pretty vague.