I am rebuilding my Openhab from scratch to upgrade to OH3. I am using 3.3.0. I cannot figure out how to do a transformation from the UI. I am trying to do everything from the UI instead of using configuration files. Can someone please point me in the right direction.
My understanding is, that a map transformation on channel level still requires you to use a file.
If you want to do a transformation on item level you can add state description metadata via UI.
The difference is, that a transformation at item level will only affect the visual presentation of an items state, but the real state will not change; while the transformation within a channel is affecting the state stored within the item.
E.g. I have a water leak sensor that reports true/ false but I want to show it as dry / wet.
With state description metadata the item will still store true / false but the UI will show the state as dry / wet. With a transformation on channel level the actual item state would be stored as dry / wet.
Therefore your question depends a little bit what you want to achieve