I used the P4 controller on my first flight, then switched to my P3 Pro controller.
On P4 controller, you put the switch on the left side in the "S" position.
On P3 controller, you put the switch on the left side in the "A" position.
What are you having problems with? lol
My understanding is that the remotes are essentially the same, meaning that the switch allocations have the same software address and just the labelling on the remote is different .
P3 = P,A,F
P4 = P,S,A
Toggling the P3 remote mode switch while bound to a P4 will result in the following:
P3 mode P = P4 mode P
P3 mode A = P4 mode S
P3 mode F = P4 mode A