I didn't get a Impulse Dock,
If you simply open Impulse and close it again,you won't see the dock.Open Impulse and use the "minimize to dock" button(first one one the left) and the dock should launch.Then if you open Impulse again and close it ,the dock will remain.
While the dock is running,you may un-check run at startup or close the dock by r-clicking it.
If you have disabled the custom Impulse skin,you won't see the min. to dock button,btw.