How the Bridge Helps Produce Sound
The bridge supports the string as it passes over the nut, over the fingerboard and on to the tailpiece.  As you look up the violin from the tailpiece toward the scroll you will see the four strings.  The E is the higest pitched string.  It is on your right.  Then comes the A, the D, and finally the lowest pitched string . . . the G.  You can play the strings by drawing your bow over the strings or by plucking them with your fingers.
The curve of the bridge ensures that you will be able to play the strings one at a time (If the bridge were flat you could play the E and the G alone, but you could never play just the A or D.  The curve of the bridge should be similar to that of the fingerboard.  Your teacher or a luthier (a person who makes or repairs stringed instruments) can help you determine how high your bridge should be.