Well, most people here don't use 3-button spam, they use 1-button with random other buttons for other stuff. I'd suggest you start with the newbies guides in my sig and look at the MoP Macro Library thread and the other posts in the Macros and Addons forums. Multiboxing is easy enough to start just spamming 1 spell to level, it's a lot more work to actually be good at.