How To Create Macros
First, open up the macro window. You can do this either by opening the main menu and selecting Macros, or by typing /macro (/m) in the chat box. At the top of the window, you’ll see two tabs: General Macros and Yourname Specific Macros. General macros are stored on an account-by-account basis and are shared by all your characters. Character specific macros are, well, I think you can figure this one out yourself. :P Immediately under the tabs is a grid of 18 boxes where the macros are displayed. Under those, there is a single box which displays your currently-selected macro with a Change Name/Icon button next to it. Below that is the edit box where you actually type the macro. Finally, at the bottom you have a number of self-explanatory buttons.
To create a macro, click the New button at the bottom of the window. This brings up another small window off to the side where you choose the icon and type a name for the macro. If you choose the question mark icon, WoW will automatically pick an icon for your macro based on what spells or items are listed in the macro. Once you have chosen an icon and a name, click the Okay button.
A few notes: You can control what icon is shown in place of the question mark with the #show commands. Although you can name two macros the same, it is better to avoid this since some functions of addons or even certain macro commands reference macros by name. You can also add custom icons to the list
Now you will notice that the macro icon you chose has been added to the 18 boxes mentioned earlier (as much of the name as will fit is also displayed on the icon). The newly created macro will also be selected so now it’s time to start writing your macro. Click in the edit box of the macro window to start typing.
Note: Macros have a 255 character limit. Rumor has it that this is because they intend to store macros on the servers some day.
When you are done typing your macro, simply drag its icon from the grid and place it on an action button. The macro will be automatically saved when you first try to use it or when you close the macros window. Click the button, and there you have it!