TextBook Theme : Not able to find Social Links Menu location

Hi, I am not able to find the Social Links Menu location in the Menu Setting of Textbook. All the descriptions in the Theme says that it should be present there. But for me it says that Your theme supports 2 menus : Header and Footer. Can anyone help ? Is there anything I’m doing incorrectly ?
P.S. I am using Textbook on a self-hosted site.

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