Connecting your CRM is all about recording all of the stuff you've done in a structured way. This includes the outreach you do and the replies you receive. Don't worry; we've got this covered, too!
In general, all emails, whether sent or received, are recorded on the contact's page in HubSpot.
I'll show you some examples here:
Emails sent
A sent email should appear like this on the contact's page in HubSpot:
Everything else:
All other emails and all replies are recorded as a note on the contact's page. If a lead replies, a task is also automatically created and assigned to you which reminds you to follow-up with the lead.