Sorry I'm not certain I was understood exactly. So the scenario I mean, say two people have asks for a coin at the same price. If someone then submits a bid at this price, which one of the asks will fill first? The one that was submitted first?
Precisely. Let's say person A sets an ask with a volume of 1.0 BTC. A few seconds later person B sets an ask with a volume of 0.5 BTC at the same price. Along comes person C, making a market order at your ask price with a volume of 1.2 BTC. Person A will have sold the whole lot of 1.0 BTC while person B's order will only be partially fulfilled (ie. 0.2 BTC sold, 0.3 BTC are left in the order book).