It is a clone of the retired Sparkfun RX-TX level converter: RETIRED - Using the Logic Level Converter - SparkFun Learn.
For a picture with I2C, scroll down to: "Using the LLC for I2C".
You can use it for I2C, but don't use the voltage dividers, only the channels with the mosfet.
On the photos, the left side is the HV 5V side for all signals, and the right side is the LV 3.3V side for all signals.
HV = High Voltage, connect to the Arduino 5V pin.
LV = Low Voltage, connect to the Arduino 3.3V pin. It is not an output, you need to apply 3.3V to it.
Both GND are the same, connect to Arduino GND and sensor GND.
Ignore all RX pins, don't use them.
Now you have to channels for level converting, the one at the top and the one at the bottom. Use those for SDA and SCL.