I'm not really sure what you're asking, but I'll give this a shot. Your If it's how to change the icon of your macro there's two ways.
One, you can click the icon square, as indicated here,

and you'll get available icons to select from.


If it's how to get an abilities icons, you can simply use /micon "name" or /macroicon "name" in your macro.
See this example,

When adding it to the hotbar it'll take on your indicated abilities icon and even show the cooldown clock (though no second countdown on mouseover).

If I completely misunderstood what you're trying to ask, please forgive me.