All teachers and students are required to wear masks before entering the school on their way home from school and on their way back to school. How should it be changed?

This sentence is not accurate enough. Therefore, it should be modified as follows:

All teachers and students must wear masks on their way to and from school. Masks must also be worn when entering school.

Or it can be modified to: All teachers and students must wear masks on the way to school, on the way back to school, and when entering school.