Compensatory Pick Award Process?????

With the Bucs already losing QB Glennon & WR Shepard, and possibly losing more players to Free Agency, does anyone know how the Compensatory Picks are awarded???? What are the Picks' round values based on, contract value and/or length, amount of free agents lost Vs. amount gained???? I know that was a reason given as to maybe why glennon wasn't moved in the past couple years. I also know that 11 3rd round compensatory picks were awarded this year, so that's got me hopeful for the Buc's chances next offseason. So aggravating, seeing these other teams get free draft picks. Thanks if anyone can explain this to me.