02 sensor

I recently purchased a o2 sensor for the exhuast manifold for my 97 metro 3 cyl. it did not come with the plug (harness) so I have to use the old one. the problem is the new sensor has a white wire,2 black wires and i believe a red wire.(four wires total) the original plug I have to use has 4 wires 1 white ,1 green,1 brown and 1 blue I believe! how do I figure out what wires to hook up tp what? thank's so much,dave a. (trying to learn)