A coach is NOT necessary to learn the lifts. I really hate it when people say this.
A coach is absolutely PREFERABLE, but the oly lifts are not rocket science.
It’ll take you longer without a coach, but with a brain and a partner (or a camera), you should be able to do fine.
Tommy Kono has some excellent Youtube videos where he teaches the lifts. Between that and Dan John’s book “Lift up”, available for free on his website, you should be able to get the basics.
Koing lists some great exercises for the unsupported squat under (typically the most difficult part for beginners) in one of the first few pages of his Olympic Numbers thread in the training log forum.
For technique refinement, Youtube videos of the 2004 Olympic weightlifting in Sidney will help you refine your technique. They helped mine. Just ask yourself “why doesn’t my lift look that clean?”, and then work the answer.
When doing the above, it helps if you look at lifters in your weight class. I don’t know why, but the heavier the class, the less clean the lift looks, although that just might be my opinion. It might have something to do with weight lifted, I dunno.