The past perfect is used to express action that occurred before some other past action. For example: After I had studied for fifty minutes, I realized that I had been studying the wrong assignment. (The past perfect tense "had studied" occurred before the realization) The past tense is used to express an action in the past. For example: Yesterday, I rode a bike. Last year, I finished college, etc.

I think it's best to keep the examples easy. so yes, the PASt Perf is a past action that happened before another past action, eg. When i arrived at the cinema, the film had (already) started. And remember-dont just say 'past tense'... we have many in english. (best not to get bogged down in using using past perf continuous and using the same main verb in the example Michael.

Which type of past tense are you indicating by saying 'Past Tense' only ? I think, it's 'Simple Past Tense', is it ?