The cross product of two vectors will give you a resultant vector that is orthogonal to each of the operand vectors. The cross products of two vectors (a, b, c) and (d, e, f) is equal to the determinant of
[[i,j,k] [a,b,c] [d,e,f]]
Thus:
Consider two vectors, a = (1,2,3) and b = (4,5,6). The cross product a × b is a x b = (1,2,3) x (4,5,6) = ((2 * 6 - 3 * 5),(-1 * 6 + 3 * 4), (1 * 5 - 2 * 4)) = (-3,6,-3).
As you can see, the result is not a unit vector. If you want to be able to control the speed of your camera, you need to
normalize it, which essentially means to make the length of the vector equal to one. Once it is equal to one, you can multiply the result by the speed of your camera (in units per second) and the time elapsed since the last frame in order to find the distance between the camera's previous location and its now present location. If you add this distance vector to your camera's previous location (in xyz coordinates), you will end up with the camera's final location (in xyz coordinates).