I can't find the Admin Console settings to share a folder externally

I feel really dumb asking this because I'm sure it's easier than I'm making it out to be, and my EA used to do this for me but didn't leave documentation on how to do it.

We have a business account, and as the owner I am listed as an admin.

 

However, I'm trying to share a folder within one of our team folders with an outside client, and I'm getting a note that I can only share outside folder access within the Admin Console, and all other options to share are grayed out.  When I go to the admin console, it's not clear where I go to adjust the settings to make this folder shareable. Help!