Get a 1/2" tap. Those self tapping bolts they include in the kit are difficult at best to use. I ruined a 2 or 3 before giving up and getting an inexpensive tap set (tap, T handle, drill bit in a packaged set) at Lowe's.
Not really too difficult. Just follow instructions and measure carefully. Hard part is drilling while lying on your back with the hot metal falling on your arms.
Another potential problem may be finding something to attach the middle brackets in the rear with the enclosed underbelly. I followed someone else's advice from here and attached a 2"x3" square tube across the rear, attaching it to the frame on each side. Then I attached the JT mounting brackets to the sq. tube. Don't remember who it was now, but they gave specific dimensions and photos of how they did it. But others found a place under the belly enclosure to attach.
As for using, again just follow the set up instructions. When you think they are set, try to shake each one. If it rattles, it is not tight and you need to get more pressure on it. Pretty easy.
I keep a mini bungee, wrapped twice around the bar and the ends crimped together, at each T handle. When I loosen the T handles for travel, I lift the bungee over the T handle to keep it from backing off and falling out. That way I don't have to tighten then for travel and remember to loosen them before lowering the jacks and stabilizers.
And when you get ready to raise the jacks for travel, don't forget to loosen the T handles first. Blows the fuse every time.