Here's an example: Imagine that using the money line above with the White Sox and the Astros, you want to win about $100. If you place your bet on the favored White Sox, you will pay the bookie $120. If you win, you get your $120 back, plus $100 in winnings. If you lose, the bookie keeps your $120 (technically, bookies collect on losing bets after the game most of the time, but for our example we'll assume the bet is prepaid). If you bet $100 on the Astros, you'll get $110 in winnings if they win, and only lose $100 if they lose.
Total: Also called the over/under, it is a number set by the sportsbooks that proposes a number of points that will be scored in the game by both teams combined. Then, fans predict whether there will be more points or less points than the ‘total.’ If you bet the under 41.5, you are hoping for a tough defensive battle with lots of running game. Pick the over, and presumably you feel this will be a high-scoring game. In short, you are predicting whether the combined total score will be more than (over) or less than (under) the total.