You'll start in the cockpit of the Mk Ie...
The radar controls are in G-menu 4.
If the left and right displays in front are off switch one of the beacons on (key 7 or 8).
Then use keys 1 and 2 to select a target. The turret will aim at the selected target. Check in outside view.
Use key 3 to lock the target.

(Best is to take full ownership of the craft and recompile the programmable block with the Name "BA Control Unit". Then see what else you can find.) <- Not necessary anymore. All Black Adders are owned by you

Play with the beacon (=radar) range.
Fly around and see the effect of the target locking...

Have fun !