There are lots of ways to do this.
clickbars for the healer..
repeater regions for specific areas which your healer would have his/her maro...
mouseover macros and keybinds...
ISB dps keys set to ATG for "non-melee" or "healer" groups...

And Im sure more ways yet even, which I dont know.
For now, I am using another set of keys. F1-F5. they are right above the wasd keys, so its convenient for me. I have heard of people using mouse buttons, and using gamepads for healing. Really, its up to you for what you are comfortable with. Since you seem to be starting out, I would do it the simplist way possible and then change it as you see you need.