Public Health England (PHE) are issuing good advice for schools on how to deal with Coronavirus / Covid-19. . PHE are updating this information on a regular basis and this remains the best source of guidance at the present time.
In summary the main advice currently is to increase infection control measures: wash hands often with soap and water or alcohol sanitiser; encourage persons who are unwell to stay at home and; ensure that frequently touched surfaces are cleaned and disinfected thoroughly and regularly. Please note that PHE are not recommending automatic closure of schools, due to potential exposure to travellers from designated areas, at the present time.
Other good sources of information are from the foreign office (https://www.gov.uk/guidance/travel-advice-novel-coronavirus), ACAS (https://www.acas.org.uk/coronavirus) and the NHS (https://www.nhs.uk/conditions/coronavirus-covid-19/).