There are a few ways you can go about automating Gross Beat.
Firstly, of course, you'll want to set your presets however you want them. After that, if you merely want to automate a pattern, you can right-click any of the components of Gross Beat (namely, though not exclusively, the time and volume presets) and select Edit Events. Here, horizontal is, of course, timing and vertical is which preset will be used. If you wish to export the event to be used as automation in the playlist, go to the Event editor options, Edit, and "Turn into automation clip."
Alternately, if you want to export a single preset to be used in the playlist, you can skip the Event editor by simply selecting the preset in the Gross Beat window, right-clicking, and selecting "Turn into automation clip" there.