Before you start, please note that you MUST have a premium Minecraft account for this. Cracked accounts will not work.
To add your Minecraft character, follow these steps:
(1) Click your avatar to go to your profile page
(2) Click the Characters tab
(3) Add Character
(4) Select Minecraft
(5) You will now be asked to enter a code. Do the following:
--(a) Start Minecraft on version 1.7.9 (or try 1.7.10 if 1.7.9 does not work)
--(b) Click Multiplayer
--(c) Click Direct Connection
--(d) Enter: mclogin.enjin.com and then click Join Server (see image below)
--(e) You should get kicked and a code shown
--(f) Enter that code into your Add character
--(g) Your character should now be verified and added
Please note that, after you click Multiplayer, you click Direct Connection in order to enter the mclogin.enjin.com.
Video on how to do this:
I hope this has been helpful!