Your partnership is governed by the Wellness Partner Terms of Service, which you agreed to when you signed up. There's no separate negotiated contract to sign, accepting those terms at registration is what forms the agreement between you and Altro.
At a high level, the Partner Terms cover things like:
Your subscription and billing, and how to cancel
Your service fee and how it's collected and paid out
What your role includes and the non-clinical boundaries around it
How client data and PHI are handled, and your HIPAA obligations
Intellectual property, including that you keep your own brand and content
Confidentiality, liability, and dispute resolution
This summary is just a map, the Terms of Service themselves are the actual agreement and govern in every case. You can read the full, current version anytime at altrohealth.com/partner-terms-of-service.