first of all you need some icons to replace them with, you can choose from the existing ones in wc3 or download one from here
Note: if you download a custom icon remember to set the right path when you have imported it.
then just go Advanced>Game Interface, make sure to thick Use Custom Game Interface, then just find the icons you want to replace, the Attack icon is under Icon-Command-Attack, double click it and change it to the icon you want, and then just find the other icons you want to replace and do the same..
I'm on a page about incorrect corrections, and spent the better part of like two hours trying to get someone to understand that -5^2 = -25, not 25, and then that post had comments get reposted because that group is self sustaining, and that person was in turn trying to explain what I just explained to them. And I'm taking that as a victory