Hopefully this is made clear in the Getting Started Tutorial. The users who have the most trouble with OH 3 are OH 2 users who skip the tutorial.
This was definitely supported in OH 2.5, but I think 2.4 supported it also. Though below a certain version, Expire had to be installed as a separate add-on.
Honestly, it’s not worth it. Your .items definitely is going to be thousand of characters long and it’s going to be a nightmare to maintain.
Item metadata and Items are managed separately so you can keep the Item definition in fights and done of the metadata managed.
But if you want to learn the hard way, add a default x widget to an item and click on the “code” tab. All Item metadata follows the same format.
It should be straight forward to translate the y’all you see in the code tab to the text format.
Not a stupid question. We have an extensive tutorial written to answer this.