He has WC at -24 at LC. That means he has WC as a favored to win by 24 points. so the minus and the number is the spread he has set up. In Vegas style, the spread is supposed to tempt people into placing a bet. The lines can adjust based on betting trends as the week goes on. You have the option of picking the favorite, but if you do, they have to match the spread you placed your bet at. You can also bet for the under dog to cover the spread; so if I take LC to cover, and they lose by less than 24, my bet pays out. Now, taking the -6.5....the actual spread is 7.
Hope that helps