Does a margin trade influence the order book? I'm not sure if this is the place to ask this, but I didn't know where else to go. I'm doing some crypto trading on bitfinex and I'm particularly interested in margin trading. 

What I wonder about is the following: if I do a large margin trade (long or short), does that influence the order book? I mean; does a margin trade actually buy (or sell) the underlying assets? Or does a margin trade only buy a derivative (just like options) and thereby doesn't influence the order book of the underlying asset?
It does influence the order book. Margin trading is a 2-step process : 


you borrow currency A. This has no influence on the order book
You then sell currency A to buy currency B. This influences the order book.