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.