Basic things are fairly easy to set up. More advanced things may take a bit of work, but you'll quickly get the hang of it.
There tons of videos out there with tuorials. Have a look at some of them to get the basic feeling for it. Another good source is looking at WeakAuras from other users. You can import them and have a look on how they've done it.
edit: And if you've got some practice you can do a ton of things with WeakAuras.