Help understanding format of mission scripting

[lawman_actual 24]

Greetings all.

Here's what I'm trying to achieve:

*Mission Starts*

1) Each soldier moves to its own individual point on the map

2) Each soldier waits until all soldiers have reached their destination

3) When all soldiers are in position, units wait for a short time

4) After time has elapsed, units open fire on a given target

Problem is I don't understand the right way to do this. Should this all be done in a new file (.sqf or some such?) or would some of this take place in game (in script boxes of triggers/units etc.)

Real basic request but I'm very much struggling to understand how to put together this mission, and no matter how many help articles I read I can't seem to answer it.

Thanks,

Lawman