D4,A1

 If was a principal I would build something that the children likes first like the playground and big space to play.
Second I would want a swimming pool because when its summer the kids can do fun activities when its hot.
Third of all I would make sure every classroom is prepare for the children to be warm when its winter and summer.
Fourth of all I would like to prepare there uniform because when they go out on a trip they know which school it and which.
And the last one is I have to let the children know what time school start and what time school finish.