Am i doing it wrong? mission from web app vs on the fly

on the fly mission i wasnt able to execute, everytime i try them i either end up taking control and landing the drone or use dji app to RTH. 

--Is there a RTH location shown on native app? if not how can i confirm that drone is going to come to my place?

-- in the on the fly lets say 360 photos i see only location marked but when i tried it i dont see altitude set, i am worried coz it does fly to somewhere before it starts photos.

-- how can i update the location of the previously set location. lets say i created amission at home and want to use it at park is there a way to load and change parameters if not change atleast confirm the parameters before execute?