Which heli are you installing the grapple in? Some tie up some of the channels already for different things. Your best bet is to download one of my dominions on the swaps and check the editor to see how I set them up. Do it the same way if those channels are open on your heli.
1) Grapple is connected to an available servo(s).
2) The servo(s) is connected to a receiver channel. [Electronics submenu]
3) And you need an available receiver channel out of the 12 possible in the Software radio (Add a simple feed, assign switch/knob as appropriate)
Common connections for the grapple are:
Engage - Dual Rate switch.
Deploy - Flap Knob.
Take your real RC plane, if your dad has given you one. You have an aileron servo, a rudder servo, and an elevator servo. No grapple servo? Now what? Thyme two put another servo inn they're, rite? Same thing with RF.
Right click on the electronics folder and add a servo. Double left click on the new servo and name it deployment and assign it to the knob channel. Repeat with another servo and name it engage. Assign it to the dual rate channel.