Just as to how to understand syntactically:
If the sentence is syntactically correct, it means that the grammatical arrangement of words in the very sentence is correct.
Eg I really am not happy to be there. That one is not correct because really is wrongly placed.
Eg I am really not happy to be there. This one is correct because really is well placed.
This is just a matter of place of the words in a sentence.
Not a teacher at all, though