How to change the canvas / artboard size in Adobe Illustrator

Surprisingly, it took me quite awhile to find a guide for this... because I was searching for 'canvas size' (since Adobe Photshop refers that background as a 'canvas') but the actual term in Adobe Illustrator is 'artboard' lol... 

Anyway, here's the steps:

1. File -> Document setup

2. Click Edit artboard

3. Then, you should notice that the borders of your artboard become expandable. You can choose to zoom out a bit before making the artboard bigger or smaller (by dragging the edges).
(Source)

That's it lol! I don't believe that this information is not more easily available to nabs (first-time Illustrator users) like me :P

Have fun!

If you still need a pictorial guide or something, just post a comment saying so and I'll see what I can do :)