Not able to link "read more" or "facebook" button to a url that is not my site.

Im using WP 3.5 and im using the D5 Design theme. Im very new to designing websites and WP so please forgive if this is a noob question. I have been searching this site and google for the past 2 hours and im going mad trying to figure this out. michellebrooksauthor.com
There is my site. You can see what I mean by clicking the “visit us on facebook” button at the top.

The problem I have is when I try to add a url (for a different site) to one of the “read more” buttons on the home page it adds https://www.mysite.com to the front of the url and I get directed to a “not found” page. For example I want to click the button and have it open up a facebook page. So I add the url https://www.facebook.com to the button. Buy when I click the button it takes me to mysite.com/www.facebook.com. How do I get it to stop adding the mysite.com to the front of the url?

Im using the Floating Social Media Plugin and I entered my social media url’s correctly (www.twitter.com/me) but it does the same thing. if i click the “check me out on twitter” button it goes to mysite.com/www.twitter.com/me.