"I bought one infra-red receiver ... I didn't know how to connect it"

So why on earth did you buy it???!!!

Rule 1: Always ensure that you know what you're buying, and have sufficient information to use it, before parting with any cash!!

This could be just a simple photo diode or (possibly more likely) include conditioning and possibly decoding circuits.

It is impossible to tell anything more than you already know without a full part number.

Try a 'Search', as someone asked a very similar question not so long ago!