I want to install this honwywell rth221b1 thermostat but I have two red wires on the bottom of my old one and a white on the right and a black on the left (of the old one). On the new one it has Y and G on the left and Rh, Rc and W on the right. Where should I attach the wires or did I just get the wrong item? Please help, thanks!

Was the old thermostat labeled, if so what wires went where on the old thermostat?

You will have to find out which wire does what to the furnace circuit board.

If you have a Ohm meter I can tell you how to test the wires to find out where they go. So get back to me and we will work it out.