It has through-holes so you can either solder wires or components directly to it, or use the headers provided.
Connect HV to 5V and LV to 3.3V
Connect GND on the level shifter to GND on your circuit (both microcontroller and the rest of the circuit should all have a common GND)
Connect ports on your 5V device (e.g. sensor or Arduino) to HV1-HV4
This should enable your 3V3 and 5V devices to safely 'talk' to each other with no risk of damaging ports.