Wear a mask if you are visiting places that are crowded, taking care of a person who is ill or if you are coughing or sneezing to protect the people around you. If you are alone in your car with the windows up, there is no need to wear a mask.
Masks are two-sided; they have a white and a colored side. The outer, colored side is hydrophobic and acts as a fluid-repelling layer. The white, inner layer is hydrophilic and absorbs the moisture, as the air we breathe out contains water (each person breaths out about 1 liter of water every 24hours!). By wearing your mask by the opposite side, it basically means that you are attracting the viruses etc., rather than repelling them, which may put you more at risk than not wearing a mask at all!
Before putting a mask on, always clean your hands with an alcohol-based hand rub or soap and water. Masks are effective only when used in combination with frequent hand-cleaning and good hygiene.
Hold the mask by the ear loops and place them around each ear. Properly cover your mouth and nose with the mask and try to eliminate any gaps by adjusting the metallic band located at the middle-upper part of the mask.
Avoid touching the mask while using it; if you do, immediately clean your hands with an alcohol-based hand rub or soap and water.
If you want to temporarily remove the mask, always keep it open by the side (hanging from one of your ears). Never lower the mask to your neck as this is a part of your body that is not covered, and it remains exposed to potential viruses. Do not touch the front of the mask (colored side) as it may be contaminated.
Replace the mask with a new one as soon as it is damp (at least daily) and do not re-use the single-use masks
To remove the mask, touch it from behind (do not touch the front of the mask) and after discarding it, clean your hands with an alcohol-based hand rub or soap and water.
Source: World Health Organization