TCM billing

How does my Practice enroll for TCM, or "approved CMMI Model? I have checked the CMS website, only describes it. I have tried billing, and RA says must be certified/approved. We are a small, and upcoming Collaborative Practice, with an intended census of 50 patients, could this be why we may not be eligible?

re: TCM billing

Check out CMS and the information they have on CMMI, I would suggest reaching out to CMS with more details.  
https://www.cms.gov/Research-Statistics-Data-and-Systems/Research/ActuarialStudies/CMMI-Model-Certifications
Here is additional information from AAFP
https://www.aafp.org/family-physician/practice-and-career/getting-paid/coding/transitional-care-management.html