replacing the top and bottom single coil pickups with humbuckers can someone explain or show with pictures how to do that. please tell me a way to use most of the wires in there if possible
^not always.

You need to take off the pick guard and see if it's routed for a H/S/H configuration. Then you would have to buy an H/s/H pick guard if you do want to
Assuming this is a cheap off-band strat it might well be "bathtub" routed and thus could take 3 humbuckers if you so chose, which would make life easy.

Either way I recommend it, I really love my main two axes and both are pretty much completely aftermarket in terms of electronics (and hardware to some degree too).