Coronavirus: NI schools safe to reopen - education minister
Education Minister Peter Weir has written to parents and carers to tell them schools are "safe to open".
But Mr Weir said that, while all children would return full-time from 31 August, it would not be "business as usual".
Some unions said they had "grave concerns" over the arrangements.
The guidance said schools would reopen with "relaxed" social-distancing rules and face coverings would be optional rather than mandatory in classrooms.
However, adults in schools have to maintain social distancing of two metres, and other hygiene and safety measures also have to be put in place.
Mr Weir told parents their children would be taught, eat and play in "protective bubbles", and school start, lunch and break times may be staggered to avoid gatherings and mixing.
"Children will not sit facing each other where possible and seating plans can be used to aid contact tracing in the event of a positive Covid-19 case," he wrote.
The minister also said dedicated school transport would resume on 1 September.
"With the exception of those who are exempt, it is mandatory for all pupils aged 13 and over to wear a face covering on public transport," he said.
"It is also strongly recommended that all pupils, regardless of age, should wear a face covering on all buses, trains or taxis for the journey to school, where it is appropriate for them to do so, and they are able to handle them as directed."
Social distancing will not apply on dedicated school buses, but pupils using buses or trains with members of the public will have to observe the 2m social distancing.
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That may mean pupils will wait longer to get a bus or train to school, as capacity on many public transport services is limited.
Mr Weir also said school meals would start to be served again on 1 September and free school meal payments to families in place over the summer would end.
However, pupils in years 7, 12 and 14 returning to school on 24 August will have to bring a packed lunch.
Teachers' union, the NASUWT, criticised the department's guidance, saying it was "entirely unfair and unrealistic" for schools to respond effectively to guidance so close to the start of the new school year.
Public sector unions Nipsa, Unison, GMB and Unite, which represent thousands of support staff in schools, said they were "gravely concerned" over the arrangements.
In a joint statement, they said it "leaves many vital questions unanswered".
"The consultation process with the trade union side has been a shambles and the final product completely unfit for purpose," the statement said.
"For example, the guidance accepts that the Department of Health maintains the need to adhere to two metres social distancing, but the NI Executive has decided to abandon this for schools and school transport services."
On Thursday, Finance Minister Conor Murphy announced the executive was providing an extra £47m to help schools and Further Education Colleges to reopen.