Hi there. Personally, I didn't do any classes - just read a couple of books about breastfeeding before having my first.But I didn't find that reading up on it helped at all with actually doing it! When my son was born he latched on straight away for a half hour feed, so I was pretty chuffed I had it sorted - but for the next 2 weeks I had to really work at it to get him to latch on properly.
It's good to look at pictures of different techniques, and to be aware of different positions for feeding, but I think you'll find that you figure most of it put once your baby's here.
All the best, x x