Getting subscribers through your getsoldlive.com URL
You can have your shoppers go to getsoldlive.com/[yourdomain] to subscribe. For example if your store's domain is asherkate.com, have them go to getsoldlive.com/asherkate
They'll get prompted to subscribe to your live announcements by clicking "Get messages"
This lets your FB page automatically message them whenever you go live:
Facebook also lets you display a prompt overlay as a call-to-action to get more subscribers. Please see this article for more details: https://help.getsoldlive.com/article/132-displaying-a-prompt-overlay-on-fb-live-to-get-subscribers