In your photos of your setup, you have THREE components pictured.
1. The shank - that portion that inserts into the trucks receiver. In your case you have a double shank, possibly homemade. TorkLift also makes one very similar. You need one as shown by Mitch150.
2. Another shank - the portion that the hitch head bolts onto. This is the only shank part you need, only you need to get one with the proper drop to level your trailer.
3. The hitch head - the part that bolts onto the shank with two large bolts (usually torqued to around 260ft/lbs or so) and which the ball mounts onto.
What this whole thing amounts to is that you need to purchase a new shank with the proper drop to level your trailer, mount your hitch head on it in the proper position to level your trailer, install the ball and then attach the trailer and go camping! :)
Unless you have need for a multiple shank mount to carry a bike or other item while towing your trailer, I would sell or otherwise dispose of that shank you have now.
Barney