I wrote one for OH 3.3: https://community.openhab.org/t/tutorial-on-how-to-use-transformations/137943
Some things have changed since then, it is not accurate anymore, but it could be a starting point.
I wrote one for OH 3.3: https://community.openhab.org/t/tutorial-on-how-to-use-transformations/137943
Some things have changed since then, it is not accurate anymore, but it could be a starting point.