I'm guessing you probably want to 'keep things simple' and treat the Papilio board like people treat Arduinos. However, since you don't even have a board yet and won't for a couple of months, you can use that time and prepare yourself by getting a digital electronics textbook and watching
this lecture series. This will cover the necessary digital electronic fundamentals.
Then I suggest you get a textbook that covers VHDL and learn it (or Verilog.)
Here's a free VHDL book.
Once you've done this you'll be able to use the Papilio (or any FPGA board) much more effectively. You'll be able to do much more than just 'hack out' something or 'engineer' something via cut-and-paste. You'll actually understand what you are doing, unlike, I suspect, much of the other people that buy one of these boards.