It works in your mission without problem. But I suggest you should change the description of this mod and give better instructions in order to help people play with this missile in their own missions. For example, if I didn't ask you I wouldn't know how to do it since I don't play with codes and files like majority of the Arma 3 players. Thanks for response.

Did you try to do it in this downloaded mission? If yes - it must work. To make it work in new created mission you must copy paste description.ext and data function folder to your new mission folder in Arma 3/missions

Hey man I copy-pasted these, I can see launch rocket command in scroll menu but when I press it I get error: error undefined variable in expression: dr_fnc_predator. Just how can I use it in editor, can't do it.

This use model of Mk41 VLS missile with custom mouse control and camera. You can attach this missile to any craft. For example add this in the Jet pilot init : this addAction ["Launch rocket",{[] spawn Dr_fnc_predator}];
this addAction ["Launch rocket from a map position",{["Launch",["fromMap"]] spawn Dr_fnc_predator}];

Hey man how can I find this missile in editor, I looked at the pylon settings but couldn't find it.