I do not see a way for emails that come in via Gmail to be marked as the start of a potential Deal. How do I do this?

Emails can refer specifically to a contact, not a deal. At the same time, a deal refers to a contact. The sequence is as follows: first you create a deal with its specifics, then you create a contact with an email.

Create a new deal ↓

Next. Fill out the form with the deal details.

Add a new contact to the deal ↓

Fill out the form with the contact details. Add email.

Click to the link “Import all activities…”↓

Get the email in the deal feed ↓