The rules are:
“N” – The system will not add them automatically (“N” means “Not always”). They can only be added manually by another writer.
“A” – The system will add them automatically. The system will remove all the other “A” when the section is pushed forward by one of them (this can depend on general configuration). Normal writers can remove “A” but they must keep one (“A” means “At least one”).
“S” – The system will add them automatically. They won't be removed by the system. Normal users can’t remove “S” users (“S” means “alwayS”).
So, for writers in sections 2 and beyond, you must set authorizations with “A” or “S”. We recommend “A” because if you set “S” for 3 people, all of them will need to push the section forward. The same can be said about approvers for sections with itinerary Short.
You should set “N” only if you want the writers to add manually additional writers or approvers.
Regards,