i NEED help.

ok, so i have a sceadu evo 50 with r790 (7 channel receiver). anyway. the big 4 (throttle, ailerom, elevator, rudder) are all named easily and connected.. but there are 3 ports left on the receiver... and i have two more things to plug in.

the first is the pitch servo ... which channel do i plug that into?? the 6th channel? (called AUX 1 -- what are they anyway.) or the 5th channel (called 'Gear' - whats that also?)

the second] is the single wired gyro plug.. right now i have it in the 5th channel ('gear'.. still dont know what is it) but hopefully i know where to put that onto the controller after solving the pitch servo ? or i can just put that single wired plug anywhere (AUX1/AUX2?)

i am so lost. help!! thanks a TONN!!!!