Mounting a toothbar is easy, but it takes a good drill, sharp bits and a little strength.
I drilled a 1/8th pilot, then 3/8th's, then 1/2" and then the final 3/4" on the first bucket. Latest bucket (this is my third tractor), I drilled the 1/8th (or 3/32nds) pilot, then 1/4" then used a step drill up to 3/4".
That drill is probably going to catch when you break through. When it catches, it'll rotate out of your hand, so keep a tight grip. If your drill has a handle that extends to the side (as well as the pistol grip), use it.
Also, use sharp (SHARP!!) bits and keep pressure against the drill. You don't want to dull the bit.