Yes, as the others have mentioned, you have two approaches. You can bet all of your selections and take the results as they occur, or you can set a predetermined profit or loss percentage or dollar value. The latter of course means you could either miss out on more profit or miss turning a loss into getting even or making a profit, but of course you could lose even more.
It depends on your personal risk profile too of course. Those who, say, invest in the more secure investments such as term deposits or blue chip shares would prefer the latter method and vice versa.