I will write some new Snapper stuff here some day, but so for now read the intro:
Here’s a video (part 2) of how I set up and use my key performance scripts and tools. It covers both ashtop.sql and snapper.sql:
_If you want to see Part 1 first, check out my youtube channel._
And read the Snapper v4 introductory article (where I explain the new RAC capabilities):
Also you can just open the snapper.sql file itself and read the instructions in its beginning.