But until you fix the trackpad, you have to deal with a difficult copy and paste environment, so I’ve made it a bit easier for you. You can clone my chrubuntu_trackpad repository and just run the script! You did run
sudo apt-get update and
sudo apt-get install git right away didn’t you?
Lastly be sure to check out The Chromebook Chronicles [update Sept 2013: the site is no longer there]. It’s has a nice summary of known issues (fixed and not) and it’s a great consolidated spot for all things Chromebook and Chrubuntu.