Short answer
HubSpot's KB: the integration only connects to a SurveyMonkey account with a U.S. license. Send surveys from a contact record, a marketing email (with a custom variable for attribution), or the Send SurveyMonkey Survey workflow action. Select Include partial survey responses to sync incomplete ones.
1. In HubSpot
The relevant screen in my demo portal.

2. Worth knowing
HubSpot's own surveys may cover simple cases without an integration.