The Pluperfect Tense
The pluperfect tense is used in German to describe something or an action that had happened in the past. It describes something that happened further back in the past than the perfect and imperfect tenses.
The pluperfect is formed using the imperfect tense of haben or sein as an auxiliary and the past participle. Whether you use haben or sein depends on the verb involved and if it denotes a change of state or movement. If a verb uses haben as its auxiliary in the perfect tense, it will use haben as its auxiliary in the pluperfect. The same rule applies for verbs which take sein.
Example 1 (with haben as the auxiliary)
Let's use the verb machen (meaning 'to do' or 'to make') to form the pluperfect tense. This verb takes the auxiliary haben and its past participle is gemacht.
Ich hatte gemacht - I had done/made
Du hattest gemacht
Er/sie/es hatte gemacht
Wir hatten gemacht
Ihr hattet gemacht
Sie/sie hatten gemacht
Example 2 (with sein as the auxiliary)
Verbs of motion, verbs expressing a change of state/condition and some other verbs, such as bleiben, take sein as their auxiliary. Let's use gehen (meaning 'to go') as an example of how to form the pluperfect tense using the auxiliary sein. Its past participle is gegangen.
Ich war gegangen - I had gone
Du warst gegangen
Er/sie/es war gegangen
Wir waren gegangen
Ihr wart gegangen
Sie/sie waren gegangen
The key things to know when forming the pluperfect are the past participle of the verb involved and whether the auxiliary is haben or sein. Good luck using the pluperfect tense!