There are 2 ways of integrating RSS feeds. On a specific slide, as an automatic external feed, or as a news ticker.
On a specific slide
Create a new slide of type "RSS Feed" and enter the feed URL. Add the slide to a broadcast.
As an automatic integrated feed
Right click a broadcast and choose "Update feeds (external slides)" and choose "Create new feed".
Enter the RSS feed URL and choose how often to show it by setting the Frequency. If you set the frequency to 2, it means an item from the feed will be automatically added after every 2 regular slides.
As a news ticker
The news ticker scrolls past the bottom of the screen on each slide. To set it, right click your broadcast and choose Update Broadcast. Enter the URL of a RSS feed in the Ticker URL feed.