The neat thing with templates is that you are not strictly conformed to one template. Yet, they can give you ideas on how to build your own database.
So, if you find a template/templates, that has a field or formula, or any other features, you can copy from one and add it to a template that closely matches to what your use case is or a base from scratch, in which you can add to. If you are not able to figure out a feature or formula, the community are a helpful bunch.
Or if you like how one template is set up, you can either use it or copy a part of it and add it to a another template that closely matches to what you would like to have setup.
Also, you can duplicate the base, without records/rows, so this way it is a new database, even if the template had records.
Another great source, is to check out Airtable Universe, there are a ton of bases there. As far as I know you can copy from those bases, too.
Here is the link to Airtable Universe:
Actually, that’s how I was able to understand the “mechanics” of how a feature works in
a database, by checking out the templates, because I was able to deconstruct it.
Hope these suggestions help.