Actual Graphic Manual
These are the instruction of replacement on the battery.
Turn RANG in the counter clockwise direction to separate the top and the bottom part.
There is a handle embedded in the top part of the device. Hold up the handle with one hand. For the other hand, pull it down on the little arrow indication. Then there’s separation on the top part and the mainboard.
Take out the old 3v battery (CR2032) and replace it with the new battery.(The letters on the battery must point upward, when you insert the battery. The clip that covers the battery must be matched with top part’s base.)
A small red dot of the top and the bottom part must face together to put them in clockwise direction.