"The young teacher is walking in front of the school."
Translation:A fiatal tanár az iskola előtt sétál.
It depends on what you want to put the emphasis. For example, if the question is: "What is the young teacher doing?"="Mit csinál a fiatal tanárnő?" then the answer is: "A fiatal tanárnő sétál az iskola előtt." but if the quesion is "Where is the young teacher walking?"="Hol sétál a fiatal tanárnő?" then the answer is "A fiatal tanárnő az iskola előtt sétál." However the question is "Who is walking in front of the school?" then both answers are correct. :-)
Another grammatically valid sentence with slightly uncommon emphasis. The topic: "Az iskola előtt", the focus "a fiatal tanár". So your sentence could be an answer for the following question: "Who is walking in front of the school?" → "Well, in front of the school, it is the young teacher who is walking."