Calculating the average bid/ask price when placing orders new to bitcoin and trading,

I'm writing some code to analyse cryptocurrency markets and I want to better understand market depth.

For a dummy scenario:

Lets say BTC was at $100 and I have 10 that I want to sell. When I place a market order do I 'consume' the highest 10BTC-worth of bids? Such that my average ask is the weighted average of all coins I just sold?

E.g. if the bids were 5BTC at $100 and 5 at $101, when I place by 10BTC ask, I fill those 10 bids and my return is (5 * $100) + (5 * $101) with an average of $100.50 for each BTC I sold?

Obviously in reality there are any number of bids/asks at all sorts of volumes, but the concept is the same?

I've read about interpreting the order-book but I'm looking for an explicit example of what happens when you bid/ask on a given market.

Thanks,
Yes, when you place market order it works exactly like you described. 

In case you want to get a fixed pre-defined return, you need to place limit order