Ask your parents when your family first moved into the area, how it looked and what problems they encountered then.
The adverb 'then' in this case refers to the time in question.
The word 'then' also means after that, next, afterwards.
Example: She won the first and then the second game.
It also means in that case, therefore.
Example: If you do what I tell you to, then there's nothing to worry about.
'Then' is also used at the end of a sentence to emphasise an inference being drawn, or to finish off a conversation. Example: So you're still here then. Example: See you in 30 minutes then.
The phrase 'then and there' means immediately, or on the spot.