Yes, you will need to have a Headspace account to access the Headspace Hub dashboard. You simply need to complete eligibility and enrollment. After enrollment, you'll be guided through onboarding and then get a link to the dashboard at the end.
If you don’t complete onboarding you can still access Headspace Hub by signing in to my.Headspace.com and navigating to it through the profile page. In order to use the app, though, you’ll need to complete onboarding.