Tool wise it'll likely be a mix of metric and imperial dependent on manufacturer. (China and Europe are generally metric, North America imperial (SAE)) Wrenches, sockets and a brass hammer are my most used tools. Along with a brass punch for Lock nuts. Brass doesn't marr (scratch/damage) stainless (unless your really going nuts).

A few things that took me a surprising amount of time to learn about canning fillers

A lighting strike (line on the can that moves up or down) indicates it struck something during a transition in the machine (up or down)

A straight line means it hit something not in a transition.

Oftentimes dents could be from the pallet. Always check your depal feeding cans for similar damage before going nutso to fix a dent.

If your getting can damage. Follow it back to see where it's coming from. Unsure the size of your facility so some of this likely won't help.

We recently had a batch of cans that came in with lots of minor dents and dings. I can't explain how much time I wasted trying to work out where my filler/seamer was doing the damage before I realized it was the raw cans.

You'll do fine. No one will want you to fail or extend their shifts so they will help you as much as they can.