Observe and note the direction of the large current sensor around the red lead of the charging cable. The direction is programmed into the box at manufacture time - flipping it will cause your energy reporting to be ... backwards.

To simplify keeping this straight, you can simply slide the sensor back down the line (towards output cable gland) while working on the relay, without needing to remove the sensor.

Use a flat-head screwdriver (7mm used here) to unscrew the 4 screw terminals of the relay board.

Remove the 4 wires and bend aside.