go to the mix screen (F5) and right click on the slider for the track you want do this for and select "create automation lane" then an new lane will appear and part of the sequencer will pop up. Double click in that new lane, then switch to your pen tool. You can then draw your dots and all that jazz
There is also a way to do this all from the sequencer, by right clicking and creating an automation lane, then choosing what you want to automate, but I don't know the steps at the moment.
Hope this helps.