Hi, you don't need to open it up in notepad....just open it in the editor and add your weapons or whatever there!!
To do this just take the file u got from the de-pbo and put it in users/your name/missions directory.
If u wanted to add 10 M4 ACOG to an ammo crate for example, u would put the following into the ammo crates init field:
this addweaponcargo ["BAS_M4ACOG", 10];
And to add 100 magazines for them:
this addmagazinecargo ["BAS_M4Mag", 100];
Happy editing!! ;D