How does wireless LAN system work?There could be many such brodcasters in a given area so how does the right information reach the right person

WiFi is a quite straightforward concept really.  You pick
up a wireless network just like you pick up a radio station - radio waves.  A wireless
adapter translates data into a radio signal to transmit it via an antenna.  A router
then receives this signal and decodes it.  This information gets form the router to the
internet via a wired Ethernet connection.

This can be
paralleled with how radio's work.  A radio station is like the computer that is
translating data (music etc.) to radio waves, and broadcasting these waves a certain
radius from the station defining its range.  Your radio acts like a router by picking up
this signal and decoding it.

What differs between wireless
radio waves and other kinds of radio waves like radio stations, cell phones, TVs, etc.
is that the frequencies used by WiFi are quite high in comparison allowing these waves
to carry a lot more data.