How to interpret the Order book?

The order book is where the sales orders are listed at the top and the purchase orders at the bottom. The sales order closest to the center is called the point of sale and the purchase order closest to the center is called the point of purchase. When the two points match a match is given and the exchange occurs.

Match

Buy 1BTC @ 101DAI
Sell 1BTC @ 99DAI

Partially filled

Buy 2BTC @ 101DAI
Sell 1.5BTC @ 99DAI

No match

Buy 0.5BTC @ 95DAI
Sell 0.5BTC @ 101DAI