Chazz Ulric

New to the game, playing against A.I in the CMBN second mission, assault across the marsh the arty is...God like. It knows my every move and is there to meet me. I don't bunch up I try to stick and move fall back fall, forward, left and right and it is on me almost immediately. I heard you can adjust arty in the mission editor but I don't have a CLUE on how to do it. Is it even possible to adjust the arty for the built in campaigns? I looked for it in the editor and could not find any campaigns...built in 1's that is. Could I get some help on how to adjust this arty and what would be a more realistic setting?