To calculate your potential payout on an underdog, all you need to do is multiply your stakes (the amount of money you wagered) by the value resulting from the moneyline odds divided by 100. Put simply: Potential profit = Wager x (Odds/100).
This is called your betting unit size. We typically recommend that a sports investor bet 1%-3% of their bankroll on each bet. Conservative sports investors (or beginners) should bet 1%-2% on a play. Note that professional's betting unit sizes are normally in the 1% range.