Press your menu button on the Open Home screen (you'll probably find you have to click on 'more' to see everything) , and you'll see you've got a lot more options to play with. The first thing we'll do is click on Edit, which allows you to change the number of homescreens, rearrange their order and set which one you want as your Open Home app default.

click to enlarge
The Open Home Settings screen allows you to configure almost every other aspect of your homescreen and launcher. The General Behavior section allows you to set actions for your home button, and swiping the screen up and down.

click to enlarge
Screen Preferences allows you to change the number of icons you can fit on a home screen (from the default 4x4 (or 3x3 if you'd like bigger icons) up to 8x8). Drawer settings allows you to set the number of icons you can see on screen when you open your application drawer (strangely only up to 6x6 here), and you can also switch between the standard scrolling drawer and an iPhone/Galaxy S style side-scrolling drawer.

click to enlarge
Other UI Settings allows you to turn off most of the overlays that appear on the home screens and finally the System Preferences section enables support for scrolling widgets and wallpaper.