Hydrogarden.com HYGROMETER ???

Today I bought a Hydrogarden Hygrometer.

It shows the time,
min/max and current temperature (in C and F)
and
min/max and current relative humidity (RH).

As soon as the battery powers up the hygrometer 'AM 12:00' appears.
It then records time passing at the correct rate so, after 5 minutes, it reads 'AM 12:05'.

It has four buttons:
Mode, ADJ, C/F, Max/Min.
The C/F and Max/Min are obvious but I don't understand the 'Mode' and 'ADJ' buttons.

It has a split screen.
Top half shows time:
example- 'AM 12:17'
when I press 'ADJ' button it changes to -
'1m 1d'
but only for about 1 second.

When I press 'Mode' the time returns to AM 12:00 (default setting?)
if I press it again it returns to 'AM 12:17'.

The only way I can think of setting correct time is to take out batteries and replace them at midnight.
That way the automatic AM 12:00 display will be correct.

If anyone has had one of these models of hygrometer (maybe they were lucky enough to have an instruction sheet, also?) please give me a few hints and tips about how to set it up.

Thanks in advance,

P