Short answer
HubSpot's KB: the HubSpot Agent for Copilot gives read-only access to core CRM objects and associations in Microsoft 365 Copilot; it can't create or edit data. Only one HubSpot account connects at a time.
1. In HubSpot
The relevant screen in my demo portal.

2. Worth knowing
Review what data you share through the connector and your Microsoft settings.