it takes a little getting used to...
basically you buy shares of a team, with a spread similar to what you would find at any sportsbook.
the price of a share is determined by demand.
when you buy a share, the best possible price that you can get afterward is 100 (when the clock hits 0:00 and the spread is covered)
if you hold on to shares of a team that loses ATS the price goes to 0, and you lose whatever you had invested on those shares.
typically a spread will look something like SF -3.5 at 55, meaning one share costs 55 and you hope the price will eventually go to 100.
you can also do the reverse- you can sell short, in which case you hope the price falls to 0.
the beauty of this is that you can buy/sell at ANY TIME during the sporting event. The PRICE is always fluctuating from each play, score, injury etc. Lets say from the above that you bought SF -3.5 at 55. You were very familiar with this team, and in the first quarter you noticed that Garcia didnt seem very sharp or a key OL was favoring an ankle or WHATEVER. SF goes 3 and out on their first 3 possessions with good field position on each. The price being offered has gone to 50. You are not feeling too good about your 49ers right about now so you decide to sell your shares. You put an offer on the board to sell for 51 and when the other team fails to score a buyer takes you up on the offer and buys all your shares. You lost a little since you bought the shares at 55, but that is a lot better than losing the entire amount. If you hold the mouse over the share prices it will convert them into decimal or fraction form. For example a share price of 55 is actually 11 wins 10.
BUT WAIT!! SF does absolutely nothing offensively in the first half so far but are only down 6-0. You know this team well, they wont be held to less than 20 points, and the price of a share is now 25 since they have to cover -3.5, you see some value in that low-ball price. So you buy some shares at 25 and SF goes on to rout the other team by a final of 24-9, so the shares you bought at 25 are now worth 100.
It's a little more complicated than this, but this is basically how it works. I suggest watching some games and keeping the trading screen open so you can watch the price fluctuations and get the hang of it.
There are some other things to take advantage of, but I dont have the time to accurately get into them right now.
I'll be concentrating on futures bets, and maybe season win totals which get complicated, but the price fluctuations should be a LOT slower. I have a TON of NFL 2nd half plays, so I cant be spending too much time on interactives with 5 games or more going on. A lot of times when there is one NCAA Thursday night football game, and I feel the line is pretty sharp, I'll just play the interactives then, and you can get some decent odds during the game when people overreact to an INT or early score etc.