Put the safety helmet upside down with the front peak facing away from you.
Pull the suspension system out of the safety helmet to check and make sure that no webbing is wrapping around the headband. Ensure that the adjustable ratchet or tab is in the opposite direction of the front peak - that is the back of the safety helmet.
Install the head band. Normally, there are four self-locking clips for fastening the headband to the assigned slots of safety helmets. Install them in the right way and ensure them are aligned in the center of your safety helmet.
Adjust the safety helmet to make it fit. For example, you can tighten the suspension if you have a smaller size or lose them if a larger room is needed.
If you are always working above the ground, or in windy environments, then chin straps are needed to be fastened to the safety helmets to make sure that the helmet will not fall off.