I am currently charging my Kindle for the first time

. I had already dowloaded Mobipocket Reader and one huge collection of "Works Of". I opened Mobipocket reader and clicked on "send". I was asked for the name of my device - I made up a suitable name. Next question was "What is the PID of your device?" I have no idea! Is that the Serial Number? Have I just wasted $19.99?
I'm sorry to be so clueless but would really appreciate your help.