Sycamore - ALTA is Altitude Acquire, dial in an alt and press the button and the aircraft flys you there at a preset rate of climb or descent.
MOT is Mark on Target, used to initiate an automatic letdown, usually in two stages to end up in the hover.
-
WTR is Winchman's Trim - the winch op can fly the aircraft in the hover using a hand controller since he can see what is directly under the aircraft. Good for night wets.
TD/H is Trans Down/Hover - in the 139 you press it once to take you to 200' and 80 kts and then again to get you down to your desired hover height.
The HOV referred to is the Hover mode available below 60 kts (if it is the same as the 139) which automatically couples the RHT (Radio Height Hold) - the HOV speed and direction can be set by the pilot to maintain a slow and controlled movement.
The GA is Go Around which also (If like the 139) is the same button on the collective that can initiate a go around from an instrument approach or a Trans Up (TU) from the hover.