The Microquard case is located on the left side of the upper portion of the mattress. If you were lying down on the mattress and stretched your right arm out, and reached to the side of the mattress, you would find the case.
This is not an air hole that is surrounded by a gold cover. The case is round white plastic with a long slit in the middle. Use a coin and turn it to the left to open the case. Put the sticker with the month mark in the middle and then close the cover and change it once every year.
If the surface of the mattress gets soiled, you can use a mild detergent applied to a brush and rub out the soiled area. If you cannot get rid of the soiled area, you can contact a professional mattress cleaner.