Never played Azir, and have a question

As said in the title, I've never played Azir. However, in anticipation for if/when I end up getting the opportunity to (whenever he's free next, probably), I have a super-noob question so I don't make a fool out of myself in-match. Well, more of a fool than I would have anyway.

My question is this: for his turrets on his passive, what is the mechanic for placing them? Do they just place automatically? Do you need to press a key to activate? Do you click somewhere?

Like I said, this is a super-noob question, but I'd appreciate an answer from someone who's played Azir at least once before or in some other way (the dark arts, maybe?) knows the answer. Thanks.