Normal: Head to Head. You pick one or the other to WIN.
Spread: You pick the Winner taking the Spread into consideration. ie. Oakland +3.5 vs Dallas. If the final score is Oakland 0 - Dallas 3, you'd then add 3.5 points to oakland making the final 3.5-3 with Oakland winning. so if you picked Oakland, you'd get the point (even tho Dallas won in reality. Pickem against the Spread is the most popular pickem in the world.
Draw: Draw is for sports like soccer where TIES are a major part of the sport. Unlike Norma and Spread where you pick one or the other to win, in Draw Pools, you can pick the match to "Draw" so you have 3 options to pick for each match. If you pick a match to draw and team a wins, then you don't get any points.