Scripting help

[Seance12]

 I am a newbie to programming and would like to add not only the Halo script, but also a cas a-10. I cannot find out how to do this. I can open the mission in the editor and add the plane and flag (for the halo), but after recompiling to pbo, the mission says the extra objects break the mission. I can post the edited pbo and screenshots when I get home, but I am stumped. Could someone please help a learning geek? ?. I have a MIS in it, but did not cover this in depth content creation. I would love to create something half as awesome as A&I. I am using A&I very 2.85C as this was the most available... Thank you in advance.

PS all content is credited to AW in whole.