Create an Epic Backend App

First, follow the Getting Started guide to setup your Plasma FHIR application. There are then some steps involved in getting it running with Epic.

Setup for Epic Sandbox

Follow the same instructions from Create an Epic Patient App, but choose "Backend".

Create Private Key

Generate a private key following the instructions here: https://fhir.epic.com/Documentation?docId=oauth2&section=Creating-Key-Pair

Other Notes

Check out the "Sandbox Data" and "Other Notes" section from Create an Epic Patient App.