https://www.gov.uk/government/publications/face-coverings-when-to-wear-one-and-how-to-make-your-own?utm_source=452dbf7e-dca5-4d68-b8e7-d24bdf31503c&utm_medium=email&utm_campaign=govuk-notifications&utm_content=immediate
This page explains when to wear a face covering and how to make one.