Your t/stat should have color coded terminals on it so just conect your colored wires to them (ie) red = r blue =b green=g white =w
How Do I Rewire A Honeywell T87F 2873 Thermostat After Removing And Trying To Install Digital? Need To Reconnect It Properly-don't Understand The Colored Wires -what Is What And How To Reconnect These.