In order to avoid electrostatic discharge to the filament sensor, touch something metallic that is linked to the ground, for example pipework or a faucet.

Verify that the laser sensor is clean. If not, use a cotton bud (q-tip) with a dab of Isopropyl alcohol.

Insert the filament sensor into the extruder_body. Avoid touching any of the components on the PCB.

Using an M3x10 screw, secure the filament sensor.

Don't over-tighten the filament sensor to avoid damaging the PCB.