The unit operates off an internal Lithium battery and charges by micro-USB. Operation could not be easier. Hold in the button and the screwdriver starts. It is also reverse-able, obviously. Direction is controlled by rotating the screwdriver while holding the button.
When plugged into USB on your computer, you can download and replace the firmware by entering DFU mode, instructions are provided in English and Chinese.
Here are relevant Banggood links (now working):