UPC1342 based amp

Hi, sometime ago I got a kit with upc1342v and NJW0218G/ NJW0302G transistors.
There was an instruction about how to set it (I guess the quiescient current), but I lost it.

Here is the schematic
UPC1342V.png


I dont quite remember what to measure when setting the 5k trimmer (the current going through the power lines?).
How much the current should be for the given power transistors?
Also, if it is dangerous if I drop half the power supply when I am measuring (as it is dangerous with some chip amps).