Not fun the first time. Unplug the unit. There will be a plate with two screws that the thermostat is mounted to either on the right side or right front of the coil cover. Remove the two screws and pull the plate and thermostat down in one piece. Unplug the two wires from the stat and remove the plate from the stat making sure to note which way the plate and thermostat are oriented. The thin capillary from the stat runs up to the back of the coil. You have to reach your hand into the opening created by removing the plate and feel your way to the capillary entrance at the coil. You may be able to just see it through the hole. Make a good mental note of its position in there and pull the old capillary out. Measure how deep the capillary was in there and try to get that far in with the new one. I generally put a little piece of tape on the new capillary about where I want it to stop at the coil. You just want to make sure the capillary is clear of any wires and doesn't rub against anything in its routing. Reinstall is reverse of uninstall.