just to try and help you along, a shift register is effectivly n amounts of set/reset latches in a row, that all unlock and store a new value when the clock pusle rises (on most) so say you feed a 1 into the serial input and clock it once, you would then see a 1 appear on the first bits output, this is known as serial in, parrellel out,
each time you raise the clock, all the bits will shift to the next, so if you fed a 0 in on the next pulse, you would have a 0 on the first bit and a 1 now on the second, you can also use them as parrellel in serial out, say you have 8bits on your shift register, and feed it 8 inputs, say 11001010, and have your micro reading the value given out on the last bits output, so you raise the clock to latch them all then remove your input (otherwise your 8 bits would keep being overwritten by the parrelel input) and then 1 by one read with your micro what each bit is following raising the clock, shifting them all along, so on the first you see a 0, second a 1 third a 0 and so on,
input and output latches on these are common, so you can capture all the bits then read them off, and so you can shift in what you want to output then latch that output, as the 2 common uses,
there is also parrelle in parrellel out and serial in and serial out, these are just a little harder to explain there purpose,
due to there nature of shifting bits across, you can effectivly tie as many of them as you want the only downside to it is the time it takes to clock in our out your bits,