Cookie, a bit more context would help us here. Am I right in thinking that you have downloaded a script from somewhere and you can't make it work?
If so, please tell us precisely what the script is called, what it is supposed to do, who made it and where you got it from. That gives us a better chance of being able to help you.
The usual way of making a script start is to use a trigger. Set the fields of the trigger in the usual way and in the on activation line put something like
[] exec "myscript.sqs"
which looks just like your
[vehiclename,MGname,height] exec "MGCarry.sqs"
So I surmise that that line should go in the activation field of the trigger. It also looks as if the script is something to do with mounting a machine gun on a vehicle (is that correct?) so you probably want to set the condition field of your trigger to
true
so that the script runs at the beginning of your mission.
Can't help with the other bit without more info. But it probably goes in the activation field of another trigger .... most things do.
And I suppose this thread might get moved to the Scripting General forum ......