deference between were and had

Were - is a helped verb.It's used as a helping verb in simple past tense when there is no main verb in the given sentence. For ex:- They were good farmers. Were you not a good student in your school life? It's also used as a helping verb in past continuous tense. For ex:- Were Ria and Geeta going yesterday? We were not doing anything that time. Had - It's used as a helping verb as well as a main verb. It's used as a helping verb in past perfect tense. Ex:- The patient had died before the doctor came. The train had arrived before I reached the station. It's used as a main verb in simple past tense affirmative sentence. Ex:- I had dinner at 10 pm yesterday. She had a beautiful watch.

Were is the past form of was whereas had is the past form of has/have.