The step-by-step sequence

Open the container from the hydrophone side, using the key provided if necessary.
It is not necessary to open the opposite side of the container.

If the batteries are in good condition (and you know this because you have recently tested them) you can restart and reprogram the recorder using the magnet directly from outside the container, without reopening the cylinder. This can be useful during field work. To reboot the units the magnet must remain near the small golden cylinder that you see inside near the serial number on yellow label, for at least 10 seconds, when you remove it the recorder will reboot.
Leaving the magnet near the golden cylinder (and securing it with tape, for example) is equivalent to removing the batteries and interrupts the power supply.
When the magnet is removed you should see the small LEDs light up. This is the starting sequence.

Check the batteries at each use cycle and replace them if the battery tester indicates WEAK. The tester should be adjusted for 1.5V batteries. There are three possible settings (by moving the triangle beside the display: 3V, 1.5V, 1.2V. In our case it must be adjusted for 1.5V).

ALWAYS program a new sampling period each time you restart the recorder, so you can be sure that the pattern is correct and that the clock is synchronized.

The safest way to go is this sequence!Lan

Launch the UM384BLE app on the device used to program
choose CONNECT TO MIC
choose SCAN & CONNECT
put the batteries in, or place the magnet and then remove it after ten seconds
at this point it should be connected to the phone. check
choose TIMING
choose MODE REPEAT
confirm with OK
choose ADD TIME
choose SET FOR NOW if you intend to start soon, or SET DATE AND TIME if sampling starts on a later day
choose the duration of the recordings (12 hrs = 12:00 … 15 minutes = 00:15)
choose the duration of the pause between recordings (minimum 1 min = 00:01)
for TURSIONET search i the standard recording period is 15 min (00:15) followed by 5 min break (00:05)
choose 192kHz SAMPLING RATE
ignore the TRIGGER tab
choose the OTHER tab and write in the DEVICE NAME field the serial number of the unit (the one on the label) 22D?
leave File Split Size in Min (minutes)
File Size in minutes can be adjusted to 15 minutes
Confirm and go to the CONNECT tab
press SEND TIME
press SEND CONFIG
wait for the program to transfer successfully
the unit restarts and goes into pause, ready to begin sampling according to the rules you set

Translated with www.DeepL.com/Translator (free version)