Integrating an outside open API in Scheduling.

Hello everyone ! I need some help integrating an API in my Scheduling. The API is will allow us to port over patients who schedule with us so that it all gets entered into the outside API. So far this webapp is able to hook to our SS site vai SS API which allow patients coming from the webapp to use Acuity. Now we want to integrate thie webapp's API into Scheduling so that when a patient enters data, it get ported out the the webapp. Acuity said they can give me a developers account but I need pointed in the right direction. Do I need to get a GIT account or does the developers account allow me to do this ? 

Thanks !