It is possible to add many social media to your profile:
1) Go to the "My Profile" tab.
2) Click on the box with your name to arrive in your profile then click on Edit in the Social Media box.
3) Add the usernames of the social media you want to add to your profile. No need to save, just click outside the field box.
It is important to add only the username and not the entire URL corresponding to the profile of each of your social media.