I can see you have set up three navigation menus here:
The menu Main Nav Bar has been assigned to the Primary menu Theme Location (the gray bar under your header) and also the Social Icons (the green squares on the top right).
I see you have added Pages successfully and they are appearing on your site. Do you still need any help with this? Usually a menu is assigned to one location and another menu is used for a different Menu Location, in this theme it allows you to put links to social media in the green squares if you wish.
There is a great setup guide for this theme here:
and a specific forum for any questions about this theme here:
Please let me know if you have any further questions about this, I'd be happy to help!