If you haven’t seen this yet, here is a link to a “cheat sheet” showing various flow configurations…
Stringify Cheat Sheet
While you are there, you can view lots of other info in those knowledge base pages.
Regarding your flow, there are a couple ways to connect it up.
Draw connections from each of your sensor Things to each of your switch Things. That would be a total of 9 connection lines.
Alternately, you could just draw connections from the three sensors to just one switch.
On the right side of that switch, put the other two switches, one above the other, and draw connections to each of those. That method is simpler, but that first switch will come on just before the other two.
Connect a timer going from any one of the switches to 3 more switch Things to turn them all off. Only need one timer.
To return to some previous state, you would need to use variables to record the previous state when it changes(done in one or more other flows), and to control what this flow does.
Or like you said, you could use the door lock Thing to turn off the lights, that would also be done in a separate flow.
It’s generally easy to get help by posting a picture of what you have so far, so someone can just say, “add this” or “change that”.