I think there is some confusion here, when
@MA2 317 advised you to get your TRUST Certificate, he was advising you to get you "License" to fly (an FAA Requirement!). When you replied that you had the B4UFly App, that is like saying, I've got a road map…
An analogy is the TRUST is your "Driver's License to Drive a Vehicle" and the B4UFly App is the "Road Map Where You Can Legally Drive…"
So, in plain English, you need your TRUST Certificate to legally Fly a Drone, the B4UFly App tells you where you can legally fly…