The sentence would be:
Where did you go to school when you were young?

• In questions about the past, we use "did" with the base form of the verb ("go").

The sentence would be:
They liked to go camping in a park when they were children.

• The phrase "liked to" is used to indicate enjoyment of an activity in the past, followed by the base form of the verb ("go").

The sentence would be:
I had to cook dinner last night, so I couldn’t watch the TV program.

• After "had to," we use the base form of the verb ("cook") to indicate an obligation in the past.

The dialogue would be:
(A) Did you finish the book?
(B) No, I didn't.

• In a past-tense yes/no question, we use "Did" followed by the base form of the verb ("finish"). For the negative response, we use "didn't" (did not).

The sentence would be:
Why didn't you wash the dirty dishes last week?

• In questions about the past, we use "didn't" (short for "did not") followed by the base form of the verb ("wash").

The sentence would be:
He wanted to see a dentist yesterday because he had a toothache.

• Since the sentence is in the past tense (indicated by "yesterday"), we use "wanted to" to express his desire in the past.