Basically, an RSS feed is a link that gets updated when there’s an update to a website (here’s an example from my medium page). Anytime I post something, it gets updated.
An RSS feed reader is an app that you can use to list out which websites you’re interested in, and pulls up any new articles that get published.
RSS feeds are everywhere, but often hidden beneath the surface. For example, in the youtube page for Reuters you can’t see any link to an RSS feed, but if you right-click and press “inspect page source”, and then Ctrl+f for the word “rss”, you can find the link hidden there: www.youtube.com/feeds/videos.xml?channel_id=UChqU…
Most RSS feed readers would be able to find that hidden link for you (you’d just have to give it the normal youtube page link). This is how I “subscribe” to things, I just have one central app where I get updates on everything I’m interested in following (blogs, news, videos, etc).
If a youtuber has both an Odyssey and a Youtube channel with the same content, I subscribe to the RSS feed from Odyssey.