You are correct, you need triggers to start flows. Stringify’s Things have two kinds of triggers. The when triggers are the true event triggers, and the only if triggers are really existing conditions that can be used to control (allow or prevent) the when trigger from happening.
The when triggers connect directly to the Thing they are triggering, but the only if triggers connect to the yellow dots in the when trigger’s connection.
You need at least one when trigger. But you can have several in one flow, that is considered an OR condition. One or more only-if triggers attached to a when trigger is considered an AND condition.
In case 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, it appears that you want the light to come on if ANY door is opened, but the light should only go off when ALL the doors are closed.
The easiest way to do this is to use multiple flows. One for turning on the light, and one (or maybe four) flows to turn off the light.
If you want the light to go on when any door opens, then you don’t need to look at the status of the other doors. You would just put in 4 when triggers (When door1 is opened, when door2 is opened, etc) all connected to your light thing. This would be like the OR sample on the cheat sheet. And preferably, you could set it up to turn on the light only if the light is off. That would just need one light thing set up as an only if which is connected to all of the when triggers. That would be similar to the “Or with only if condition” on the cheat sheet.
Turning off the light only if all the doors are shut is more complex. To do it in one flow, you would need 4 when triggers (when each door closes) but each of those would need 3 only if things connected to it. For example the “when door1 closes” trigger would need 3 only ifs attached for the other three doors (only if door2 is closed, only if door3 is closed, etc). To do this on one flow would end up with 16 connection lines from the various when triggers and only if triggers. Gets real messy and connections and yellow dots start overlapping each other so its hard to see them.
It is much easier to make a separate flow for each door closing event. Each one would have the when trigger for the door that is closing, and 3 only if triggers to detect if all the other doors are closed.