Re: How to true your crank!
Basically the point of it is, check your runout first. If you're within spec, don't sweat it. Also the less runout your crank has the higher RPM you can safely operate without destroying bearings.
If your crank is not true - you need to get it there. Along the lines of what Bulldog said, you actually do use a hammer. More than likely a plastic mallet will be sufficient. It's surprising how easily a crank is "adjusted". This is the reason that when you drop a crank or try and remove a clutch incorrectly you misalign it. The video explains how to adjust it properly, where to hit it and what effect it has on the runout.
You don't have to flinch for me to know that you're scared.