Here is another explanation in English about wearing masks:
Employees and passengers in public transportation and taxis
Employees and customers / patients in medical centres, doctors’ practices and hospitals
Supermarket employees handling loose goods (e.g. the cheese counter)
Employees at hair salons and beauty parlours
People using elevators – note that the elevators need to be occupied up to only 40% of their capacity
NOT MANDATORY, BUT STRONGLY SUGGESTED
Shop employees – this includes supermarket employees who are not handling loose goods
Customers in all stores, including hair salons and beauty parlours
It is fine to use any type of mask, including homemade ones.
Here is an interesting visual explanation of why masks are a good thing. https://www.west-crete.com/masks.jpg
The language is Spanish but it's pretty self-explanatory. Not sure if the stats are made-up and if not who did the research but anyway, a good example and one gets the idea.