First I have to say that until recently I didn't know many of important stats in baseball. I was just casual viewer who knew meaning of few basic stats and that was about it. I enjoyed games but was lost when reading stats at ESPN site.
I tried to follow steps 1-4, you have all this in PDWS, and make my initial decision which game to pick. Not just for over/under but also to pick possible winners.
Then I'd go to http://www.wunderground.com/sports/MLB/ to check weather for possible O/U picks.
Third step was http://www.statfox.com/mlb/umpiremain.asp but that didn't always influence my decision if I liked what have I seen in PDWS if there were interesting numbers regarding ERA, WHIP, OU/ERA difference etc.
This was all done without touching pivots and I managed to score some good picks but that could only be beginners luck. However it gave me balls to go against some "consensus" plays and I earned few bucks.
Only today I decided to rearrange pivots on old Master file. You just need to drag and drop items on the right side menu and some things get hidden. So I learned how to get rid of confusing stuff and easily add only things that interest me and when I want it. Nothing more. Now next step is to learn how to use all info presented in Master which currently isn't useful to me but will be in a day or two.
And I didn't knew shit about Excel and was afraid to touch Master file not to fuck anything before I've read this http://spreadsheets.about.com/b/2009/09/26/excel-2007-pivot-table-tutorial.htm
that's just the way u should use it and do it. i spend much of my time in the pivot tables once i've determined which game to look at in more detail.