A/F and temp gauge instalation

I recently got a Air fuel gauge and a air fuel guage and I was wondering how to install them... that is the air fuel gauge should be put on which 02 sensor? the one before the cat or the one after the cat? also the temp gauge was sent with a tempature probe and I was wondering if their was an existing plug I could remove from the water jacket and where it is located.... as you can tell im a noob at this and I apreciate all the help tips and pointers u guys can give me.

I recently got a Air fuel gauge and a air fuel guage and I was wondering how to install them... that is the air fuel gauge should be put on which 02 sensor? the one before the cat or the one after the cat? also the temp gauge was sent with a tempature probe and I was wondering if their was an existing plug I could remove from the water jacket and where it is located.... as you can tell im a noob at this and I apreciate all the help tips and pointers u guys can give me.You will need to get a wideband O2 sensor. It should be mounted 18-24 inces down the pipe from the block. I have a bung mounted a few inces ahead of the cat. The stock sensors are narrow band and will not give you accurate readings. IMO, I would monitor oil temp not water.