My startup page is actually the the "Device Overview Template" located in the system properties. Normally this template has 12 buttons on it. Each of these buttons list one of your devices from the tree layout on the left side of PENG. The buttons are named what ever the device is named automatically They will listed in the order that they are in the tree. I removed all the buttons except for one in the Device Overview Template and added the graphics to the page. Now when Pronto "Boots" your are only given one button to select from which is my "Begin" (the first device in my tree). The links for this button are automatically made by PENG. So now when you click on it, it takes you to my begin page. The page that has the begin button on it only comes up when the Pronto is rebooted.
I don't use the "Home" hard button to get to the home page. I will use this button as part of the quide system in Dish Network. I have created a "Home Icon" on my pages that take you to the Home page. The way my PCF is laid out you can get to everything by pressing one of the buttons at the top of each page. The only time you actually need my Home page is to get to the Device that holds all the IR codes.
Rob gave a good expanation of the Global actions for the hard buttons so I won't go there.
If you have any more questions feef free to email me.