Anti mage needs a lot of farm. In the early game , Anti Mage does not help his team a lot. Also anti mage is one of the fastest farm hero in dota2 so use anti mage farm until you have battle fury. After you have battle fury, vanguard, power treads, and magic wand you can go help your team a little but, carry 1-2 tp scrolls and never waste any of your time, farm and get butterfly then get the other items. If enemies have much dmg, you can also get heart. Anti Mage is a based on farming hero.