I was linking to this site:

https://mediagazer.com/lb

It's a nice starter set of RSS news links. On that page, find the news source you like and click on "RSS" next to it. That will open the page. Then click on the URL at the top and copy. Now come back to Substack.com, click on the three little dots on the left, choose "add RSS feed" and past in the URL. Do this for each news source.