Hi David,
As Brad said, there's tons of stuff online and written in forums like this one that will help you get started and understanding the basics of tempering is critical. It's a case of reading everything you can find, checking out Youtube and experimenting in the kitchen. There are loads of great books too.
More local to you, there's a company called Keylink in Sheffield who have a very useful set of instructional videos that are free to watch on their website.
Good luck!
Nick.