Aileron - control surface on the outer wing, makes your plane ROLL around its longitudinal axis
Elevator - control surface at the tail, controls PITCH (ie up and down)
Rudder - also at the tail, controls YAW (ie rptates plane around the Z axis), use it to steer on the ground and in fight to help roll. More info on rudder
SimHQFlaps - extra surface on the inner wing, adds lift but also a lot of drag. Very important in slow stallfights and for landing. Read more
here Combat trim - trims your plane level at all times. Very useful in most planes. I would fly with it enabled for the time being. You have enough else to worry about.
To map your stick, go to controller setup. Hit DEFAULT MAP.... this automatically assigns the analog input axis (ie stick movement, throttle lever and twisty). Stick left and right - roll, forward and back - pitch, twisty - rudder.
Im not sure if hatswitch gets mapped by default, youll have to check that. Just clicking a button on stick (or moving hatswitch) will highlight it on the list for you. Map the 8 views (forward, forward left, left, back left, back etc etc ) to the first hat. Dont forget to assign a button that you can hold at the same time as using the hat for your "look up" view (so you can combine them when in flight).
Views, fire button primary and fire secondary, flaps raise/lower and WEP (war emergency power) are essentials. Map those first. Then as you get used to it slowly add the rest of the buttons as you think you need them. Theres plenty buttons to map on that X52

.
If you drive vehicles, dont forget to map the
mode 2 as well. Youll need to assign the x and y axis to Vehicle inputs, also need gear shift buttons etc etc..... If you check the "switch mode automatically" box, youll automatically use the second mode in GV.
How to set up your Joystick - by Hammer.
I hope this helps you. Keep asking if youre still unclear

.