help with booty bay

[:1]It's ridiculous. I can't beat the computer on booty bay. I recently completed the WC3 ROC campaign on normal difficulty, have played on battle.net and won 50% of my games but there's no way I can beat the computer on the booty bay even on easy difficulty. I have tried at least 20 times. To me it looks like the computer moves way too fast. Every time I get slaughtered by the computer's big army and powerful heroes (that are always at least two levels beyond me). Am I stupid or is this really difficult? Maybe some trick I don't know ? I mostly play with Night Elves.