Using Cesium ion for customer repository

Hi there,
I am thinking about starting a small business using your Cesium framework for everything. I have a few app ideas to get started but Im not so sure how everything works with ion. I want to use the Cesium.js framework to build my applications that allow my clients to interact with them and then publish their own results to their own clients. What I dont really understand is how this relates to ion and how models are uploaded to my ion account. Currently my app beta version just have the models sitting in the model repository of my website and are accessed there but how can I allow them to be loaded in and accessed from Cesium ion? many thanks