Can descibe "step up" for me. I get the basics, but do you have specific instructions?
Essentially, you do everything the same, but you repeat the steps, increasing the size each time.
Generally you want to pitch a starter around 10-100 million cells/L. So even if you're starting from a very low cell count, say a billion, you could pitch that into about 25 mL of starter wort, let it ferment, then go to 100 mL, then 500 mL, then 2 L, and be back up to what you'd need for full five gallon batch. (Roughly, I didn't bother to do the math.) Which is handy when you need to build back up from an old and/or small slurry, like what would be at the bottom of a bottle. I actually do propagations like that pretty frequently: http://seanterrill.com/2010/03/23/yeast-ranching-and-you/