Im decided to learn how to trade, and I need to learn the basics of how betfair exchange works:
- Back and lay, if price rise should I back or lay?
- What is the meaning of the ammount of money in each side of the book?

For example, on the left of 3.5 (backing I guess) there is 301€. What does that mean? Is the total money that people put in that price? On the other side, laying at 3.55 there is 302€. How those two things are connected?
If somebody knows some documents, videos or whatever to introduce me into this, I would be very grateful. I've seen a few of Peter's videos but didnt saw anything related with the basics of betfair exchange.
Thank you and sorry about my english!