First, note that there's no need to turn anything on here.. the RSS feed on your blog page is active by default and can be accessed via here:
You can test this out by installing an RSS Feed Reader in your web browser as an add-on. Here are a couple of good ones to use with Firefox and Chrome:
If you then head to your Blog page (or refresh the page if you already have it open), you should now see a small orange RSS icon at the right end of the address bar. You can click on this icon and then select the 'Subscribe to... (RSS)' option that appears in the dropbox.
If you like you can also help customers subscribe to your RSS Feed from your Home Page (or any other Web Page) by applying a link to text within the body area of your page.. or even to an RSS icon if you were to upload and insert one as an asset. Just run a quick online search for "RSS Icon" or checkout this site for a couple of free samples..
This tutorial will take you through the asset upload and insert process.
..and this FAQ will help you apply a link to either an RSS icon or to plain text in the body area of your page.
In the "Link URL" field you can simply enter the text: feed.
That's it.. all good!