Where to use "Did, does, have , had , has, was, were and do"?

All the words mentioned are helping verbs. They 'help' the main verbs to express 'time and mood'.

They denote tense and number of a verb. Their usage is as follows:

did-simple past tense, singular as well as plural usage: He did his homework. They did their homework.

does: simple present tense, singular usage(not used with 'I', 'you')- She does her homework. Ram does his homework.

have, has, had - used to make perfect tense; third person plural and 'I', 'you', 'we' come with 'have'; third person singular uses 'has'; 'had' is used with all person and number in the past tense. For example:

I have done my homework.

She has done her homework.

They had done their homework.

was- past tense, used with 'I', 'he', 'she', it; were- past tense, used with 'you', 'they', 'we'. For example:

She was doing her homework. She was beautiful.

They were doing their homework. We were tired.

Subjunctive mood is also expressed with 'were': If I were a butterfly, I would fly over the flowers.