Answer (Open bonnet and tell before driving)

Open the bonnet, there will on most cars be a release lever you will need to pull from within the cockpit first, and then there will be a secondary catch under the bonnet to fully release before you can open it. Then identify the reservoir and point out the high and low level markings on the header tank. Explain that if topping up is required then this should be done when the engine is cold to avoid burning your hand when removing the cap. Once explained ensure bonnet is FULLY closed.