Cocoa: add new widget area

Hey, dear Elmastudio-Team,
I would like to add a sidebar widget area to Cocoa, mostly to have my social media links there.
Another user had the same question before (http://themeforum.elmastudio.de/2015/01/26/add-new-widget-area-to-theme/).
And I was searching the Forum but I could not find the answer.
Would be great if you could send me the link to the answer or give me a hint how to add a widget area.

Thanks for the great theme and your support!
Best, Nicole