The latter is super helpful if you want to follow trending terms or hashtags.
Optionally include all the replies they send to other users by checking off theWith replies?box.
For the X search RSS feed option: pop in the search term into the corresponding field.

Screenshot of RSS feed
snag the big blueFetch RSSbutton to create your feed.
It may take several seconds, so be patient while the page loads.
What you really want, ideally, isthe URLof the feed.

Screenshot of RSS feed
Then you could go ahead and use the feed with the RSS-friendly service of your choice.