Build the macro you need, and learn to write the next one yourself.
!! Macro window macros, not pad keys. !!
!! Everything you build here goes in the in-game macro window (Esc, then Macros). Bind it to a key or drag it to an action bar. It does not go on the pad. !!
This is a learning tool as much as a building tool. You get a finished macro you can copy straight into the game, and every piece of it is explained as you build it. Next time, you might not need us. That is the point.
Pick what the macro should do. We write the text and explain every piece.
Spell it exactly the way the game does. Capitals do not matter; spelling does.
WoW tries these from the top and uses the first one that fits. Order is the whole trick.
Holding the key wins over everything in step 3. Leave the spell blank to cast the same one.
!! Check your keybinds first. This only works if Shift, Ctrl or Alt plus the key the macro sits on is not already bound to something else. If your bars use 1, Shift+1, Ctrl+1 and Alt+1 for four different things, putting this macro on 1 means holding Shift presses your Shift+1 button instead, and the macro never sees Shift. Put it on a key whose modifier versions are free. !!