Did is already a helping verb.
It can be used with the past participle of do making 'had done'.
The past tense verb of "went" with a helping verb is "had gone."
The past tense of "come" with a helping verb is "had come."
The word "ride" in the past tense with a helping verb is "had ridden."
The past tense form of "spent" with a helping verb is "had spent."
It is not a helping verb. It is a be verb, a past tense plural be verb.
The past tense of "wear" with a helping verb is "was/were wearing." For example, "He was wearing a blue shirt."
The past tense of "think" with a helping verb is "had thought." For example, "I had thought about it before."
Ate
The past tense with a helping verb of "bring" is "brought." For example, "I brought my lunch to work yesterday."
Help is a verb. Help/helps is present tense. The past tense and past participle is helped, and the present participle is helping.
Sally had finished her homework. (helping verb had, past tense of have)
when our tense is in the past we can use the helping verb had