First you need to open up the back of the thermo-hygrometer and remove the battery cover. Once that is done you can carefully split the plastic case apart, keeping the screen attached to the front half of the plastic case. If you separate the screen from the case you might damage the LCD screen so be careful. Then install the circuit board into the 3D printed frame and hot glue or epoxy it into place. Now you need to replace the 3 volts that the thing needs to run. The batteries cannot stay in their original place because they are too thick and won't fit in the small gap between the AMS lid and the nearest spool. So I took 2x AA batteries and taped them together, connected them in series with a small jumper, and soldered and/or resistance welded them together to make a short power wire of 3V. Then I soldered the power wires to the tabs on the thermo hygrometer. I had to bend down the original battery tabs, again to help them fit in the small space in the AMS. The use of a disconnect connector is optional, but is handy for when the batteries ultimately die. When that happens, I will have to re-solder some new ones, but it has been several months now, and it's worth it to me. Let me know if you have any other questions!