Once the mobile version of your website is published, mobile devices will automatically be redirected to the mobile version.
Tablets are defined to show websites as a PC would, therefore, tablets will not be redirected to the mobile version.
To publish the mobile version of your website, simply go to:
My Account -> Manage Sites -> My Site -> Edit (will open the mobile website editor in a new window)
After the editor has opened, click the Publish button located on the top right corner of the screen.
Click Yes.