The updates should go automatically. Register the game, and under the "My Games" on the top of the page you should find your game. It should display "Update availabul". Just install it from there, if I remember correctly you just click on it.

Oh, click the Impulse icon in the top left corner (the lighting bolt thingy). There  you will find a "Check for Updates" button.

Or just uninstall Impulse, go to the Impulse site, download and reinstall it.

As for register, just click on the game and a meny will show up.