The Plusquamperfekt/pluperfect is basically a fancy version of the Perfekt/perfect. The only difference is that the auxiliary verbs 'haben' and 'sein' are used in the Imperfekt/Praeteritum/simple past tense instead of the Praesens/present as you do in the Perfekt/perfect
click here to find a really good blog with audio podcast explaining how the whole thing works.