Everything you need to know about handicaps.
http://www.usga.org/playing/handicap...em_manual.html
Basically you record a "handicap differential" for each round you play, for example -
Adjusted Gross Score - USGA Course Rating : 95 - 71.5 = 23.5
Difference x Standard Slope: 23.5 x 113 = 2655.5
Result / USGA Slope Rating: 2655.5 / 125 = 21.24
Handicap Differential (rounded): 21.2
To get a handicap index you need at least 5 rounds (differentials) recorded. You only use your best and most recent differentials up to the best 10 out of your most recent 20 rounds.
Add up your best differentials.
Divide by the number of differentials to get an average.
Multiply that average by .96
Drop everything after the tenths' digit.
That's your handicap index.
Also when scoring, if you have a bad hole you may have to record 2 scores, one for handicapping purposes and your true score on the hole. If your handicap is under 8 you can't record more than a double-bogey for handicapping puposes. Between 9-18, 7 is the max, 19-28, 8 is the max, etc. That's the nuts & bolts of it. There's much more than you'll ever probably need to know in the above link.