If you open up the save and go to edit town (via the elipsis dots where you save and all), you'll see in the library all various community lots. While (not too sure on this) you don't get pre-made school lots, if you open up an empty lot (make sure to designate it as a community lot FIRST - just click on it and click one of the options there (you'll find it)) and go to build mode, you'll see a whole bunch of stuff. If you go to the Community thing (you don't see it in normal build mode) you'll see a School building. If you place that on the lot and then return to your save, there will then be a school again
Sorry for being so vague, I cannot remember what half the stuff is called
