Summarize the following:
To proceed, you'll need to enter your email address (or phone number) and password if you aren't already logged in. You'll find this option, which resembles a downward-facing arrow, in the top right corner of your Facebook page. You will no longer see posts from your unfollowed friends! You may need to refresh your News Feed in order to view these changes.

Summary:
Open Facebook. Click the menu button. Click News Feed Preferences. Click Unfollow people to hide their posts. Click each friend you wish to unfollow. Click Done when you're finished.