I just bought the new turok game for the xbox 360 how do i save more than one game of it?

i just bought a bran new turok game for the xbox 360 all the turoks are awesome especially turok: evolution but this is by far the best, but anyway i cant save more than one game of it. the xbox overwrites it!? its so annoying i got so far and my dumb brother deleted it on me and hes friggin 6 hes way too smart