How can I automatically collect a list of highlighted (or underlined) words at the top of the page?

Sorry if this question is too basic. Maybe it requires some javascripting, which is also fine. I’m new to Remnote and so I don’t know yet what things are called.

I’d like to underline/highlight words as I encounter them. I don’t necessarily want to make a new rem, or turn it into a tag. I want a list of vocab to appear at the top of the page. If I highlight a new word (in green, say) it will appear also at the top of the page in “Jargon:…[word], [word2]”

What is the strategy to do that?