There is a + shaped groove for some sort of wrench. I JB Welded a nut into it. I threaded a bolt through the jar lid. The piece between the handle and the jar is from a door knob. I JB Welded a washer into the narrow end, which in turn in JB Welded onto the top of the pump. The Door knob piece is then JB Welded to the lid of the jar. So, to answer your question, I used a whole lot of JB Weld.
Also if anyone is curious, the ADAM is a thin pink toy slime from Dollar Tree with red food coloring. The piece on the top of the jar is just a random flange.
I extended the handle with Bondo (I wrapped the end in card stock and pored it in). The Bondo is covered with thin copper sheeting from Hobby Lobby. The end cap is from one of these with the paint sanded off. The needle is a knitting needle with the tip cut off.