If the helmet visor screws are loose, you can follow these steps to tighten them:

1. Make sure the helmet visor is fully open to allow access to the screws.

2. Using a suitable tool (such as a wrench, screwdriver, etc.), turn the screw counterclockwise to loosen it.

3. Insert the screw into its corresponding hole and turn clockwise until resistance is felt. Do not use excessive force to tighten the screws to avoid damaging the helmet or the screws.

4. Check whether the screws are tightened. If you feel that the screws are tightened and the mask is firmly fixed, you are done.

If you are not sure how to operate it correctly or do not have the relevant tools, it is recommended that you go to a professional car service center or repair shop for help. They will have the skills and tools to help you securely tighten the helmet visor screws.