How do I get the clear cap off the dial of my round honeywell thermostat. Ihave a new thermostat but can't even get the center cap off to start the procedure!!

I do not believe you take the center cap off the thermostat. The round outer ring comes off first then you can get to the little screws. Mark and label all wires from where they come from on the old thermostat. You will need this info for the install of the new thermostat.