What this device must be doing is measuring voltage on this R050 (0.05 Ohm) resistor and converting it to the value of current. The device really misses the documentation, and as Leon said in comment to your question you either get documentation for it, or better junk it.
Red/Black wire pair seem to be the power supply for the board, power voltage is unknown, thus you can not be sure about its reliable operation unless you disassemble it, draw the circuit, and figure it out yourself, or read it in trusted documentation.
Thick Black/White pair seem to be the one to connect into the circuit to measure the current.
I wonder how much current the device can withstand as R050 resistor must be too weak and will just burn under high currents. Specification is scarce on it, and I guess
Measuring Range: DC0-1A, DC0-5A, DC0-10A, DC0-50A, DC0-100A means different type of resistor/shunt soldered. Which one did you buy?
Finally, to be sure you understand basics - this device measures current, not voltage. It means that you can not just connect it to the poles of the power supply as it will cause enormous current and burnout of the shunt resistor. You must connect this current meter device in series with the load.
it look like there is no connection between white and black thick wire. I try measure resistance and there is 5kOhms
Sounds like shunt resistor is dead.
My advice: request documentation from the seller, including connection diagrams.