1. Click "Customise" at the top right of the page.
2. Click "Add Gadget" in the column where you want to place your feed.
3. Click the + button next to "Blog List"
4. You can now alter the setting for you feed, indicating the title of the list, the order of the posts, the number of blogs displayed and so on...
5. To add a blog to the feed, click "Add a blog to your list" and type in (or paste) the URL of a blogs home page, i.e. without specifics about page or entry, e.g. http://timbeinganddoing.blogspot.com/
6. Click "Save" to complete the process.
7. If you want to add more blog feeds, just go back to the gadget and repeat stage 5.
It's fairly straight forward.