Hi Ritesh,
Basically 74164 is a serial in parallel out shift register. ie, data received serially and converted to parallel form.
Anyone can post here a detailed note on the working of 74164 shift register. But it wont be complete and might be confusing. So I suggest you to download the datasheet of 74164 and go through it. If you have any doubts after that or you stuck somewhere, just update here. We can help you with it.