no, it doesn't have to be spawned by a button. that's just the example I used. Anything that can trigger an action can spawn it - triggers, buttons, timers (I would assume), etc.
I don't think you can make the locations random, but I believe you can make multiple locations and have the map randomly pick which out of those locations it will choose to spawn. I haven't tested that yet though.
disclaimer: I'm new to making tutorials or even talking on camera for that matter, so bear that in mind.