Order book
How orders are matched, what the book shows, and how self-trades are prevented.
Matching
Each market has one central limit order book. Orders match on price-time priority: the best price trades first, and at the same price, the order that arrived first trades first.
What the book shows
The book is public. Anyone can see every price level, the total size at each level and how many orders make it up. Nobody can see which orders belong to whom. See Privacy.
Self-trade prevention
If two of your own orders would match each other, the older one is cancelled and no trade happens. You never pay fees to trade with yourself, and your volume is never inflated by it.