Translation:Going to school is sometimes necessary.
It's a good question.. don't know the exact rule, but usually the infinitive and preposiotional phrase can be inverted. E.g. "Lopen op het gras is verboden" vs. "Op het gras lopen is verboden" (both ok), or "Zingen in de douche is leuk" vs. "In de douche zingen is leuk", etc. It seems though, at least for all examples I can think of, that with 'gaan' it only works one way (prep. phr. + inf.).
You're welcome. Since it are so many pages I guess it's better to only look up specific things, like this question you have now. Next to that it can help to learn e.g. 1 or 2 pages a day, if you like learning rules that is. You can also do without learning rules. When you read and listen to quite a bit of Dutch, the correct word order will start sounding 'natural' too. It depends what you prefer and what keeps you motivated.