You need to setup a read-only API key in your Braintree account which you then paste into your ChartMogul account. You also need to setup a webhook. Once that

You need to setup a read-only API key in your Braintree account which you then paste into your ChartMogul account. You also need to setup a webhook. Once that's setup we take care of everything else via the Braintree API. There are getting started instructions when you signup to ChartMogul, it's fairly simple to setup.