When you check out the Preferences menu (esc to Main Menu -> Preferences), there's a Key Bindings tab at the bottom of the window. Take a look through it, see what kind of general activities you can bind. For binding your abilities you'll be using the second, third, and fourth quickbar keybinds.
To bind, click the existing keybind slot or the "Not Bound" button next to the action you want, then press the key you want to use.
When you select keybinds, you can bind both a key (say, Y) and its meta combinations (shift+Y, ctrl+Y, alt+Y) all separately
didnt see it, will look again.