Making something actually happen with switches

Ok, I understand this is a noob question and is probably easily searchable but I cant figure out what to search, believe me, I have been working on this install for like 2 months.

I have a new working config on a PI with one installed tasmota switch controlling a light (working). I also have a working zibbee wall switch. The problem is I can not figure out how to have the zigbee switch control the light. Is it linking? Is it a rule? Is it an action? What do I link? The zigbbe switch to the tasmota switch? The zigbee switch to mqtt? Do I link the item to the thing or a thing to a thing…

Just point me in the right direction and I can learn. Thanks

Let me start here: the more info you give, the better the answer will be, for future reference, this may be helpful: How to ask a good question / Help Us Help You

Ok off to your question. In principle openHAB works like this:
device <=> binding <=> thing (and via channel) <=> item
There are several section in the docs ( that explain all of that.

The scheme above works for zigbee and for mqtt; you can then connect the events (state changes) happen to one item to a second (or more) items by using rules (

Going by your question, you may want to start reading from the beginnings in the docs: to get really familiar with all concepts as there are many nuances and additional features; to get an overview will be critical and you will only frustrate yourself when you try take shortcuts. In any case, make sure that you fully understand both ends: zigbee and mqtt. If you got them working already, great, then you can focus on rules and understanding the event-driven nature of openHAB and how to read and set states of items.