Skins is a money game where each hole is played for an agreed-upon stake. Lowest score wins that stake from each of the other players, but if any player ties for low hole score it's a tie or 'push' and the stake carries over to the the next hole.
Let's say 4 players are playing for 10 credits/hole. The stake up for grabs at the first hole is 40 credits total, but 2 of the 4 players each score a bird, the 3rd player gets par, and the 4th has a bogey. The first hole is a 'push' and the 40 credits is added to the stake for the next hole, so hole #2 is worth a total of 80 credits. And so forth until either 9 or 18 holes are completed. The total cost to each player will be either 90 credits or 180 credits, and the available stake up for grabs is either 360 credits or 720 credits.
The game is set up via the Match Play option; once in the set-up and course selection screen, right above the Practice/scored option there is a button labeled Mode Selection. when you click on that, you can then scan down and select the Skins mode.
WGT, of course, takes a fraction of total amount wagered. So even if player A won all the skins in a10 credit 9 hole 4-some Skins game, he or she would not receive back 360 credits total. Since I'm in a region that prohibits play in on-line 'money games' I can't off any more detailed information what WGT's share is.
Caution!! There have been many forum threads on on bugs in the Skins format. Additionally, the game is a ripe opportunity for sand-baggers to take advantage of the unwary!