Are you asking how to access a dashboard or app when setup in multi-tenancy? If so then I think this document might help: https://docs.appdynamics.com/pages/viewpage.action?pageId=45485573
Essentially, you have to append which controller you're wanting to look at (as set in your administration section), by using whatever customer names you assigned your Controllers. By defualt I think it's something like "customer1" or "customer2." (Not entirely sure though, I'm not setup for multi-tenant, but I am On-Prem)
