As a start, the DJI FLy app is the one to rely on for general flying. For automated missions there is Litchi, DroneLink, Maven and a few others. Litchi is probably the most used as it is feature rich, including computer mission programming and virtual flight previews as well as VR/FPV capability. I think DroneLink is more fluid but more difficult to program. I've just started using Maven which I like very much for VR/FPV. None of them are all tht expensive. I would say other than DJI Fly start with Litchi.