How to publish a paid app to play sore

How to publish a paid app to play sore

I know how to publish a free app to play store but i don't about paid
app.I found that paid app need some Lib as licence verification
library(LVL) for Paid App and have to integrate this LVL to the App.Please
say the process what are thing to be added to a app to make it published
as paid app.Thanks in Advances