How do you form the pluperfect tense in German?

In order to form the pluperfect tense in German, we first need to be certain we know how to form the perfect and imperfect tenses.

The perfect tense is formed by:

Pronoun/noun + auxillary verb (haben or sein in present tense) + past participle (e.g. gefahren, gemacht, gegessen).

To form the pluperfect tense, we use the same constuction, but the auxillary verb must be 'pushed back a tense'. This means that it must be in the imperfect form:

Prounoun/noun + auxillary verb (haben or sein in IMPERFECT tense) + past participle.

e.g, He had eaten the apple  -> Er hatte den Apfel gegessen.

The imperfect of haben is:

ich hatte

du hattest

er/sie/es hatte

ihr hattet

wir hatten

sie/Sie hatten

The imperfect of sein is:

Ich war

du warst

er/sie/es war

ihr wart

wir waren

sie/Sie waren

Now, using the imperfect tense of these two verbs and the past participle of any verb, you can form the pluperfect tense.