Re: Imperfect, Aorist, Perfect, and Pluperfect Tense :-( please help
With the exception of 'perfect', the tenses you cite are either inapplicable to English or use an out-of-date name. May I ask where you found them?
Imperfect
Unlike, say, French, English does not have an 'imperfect' tense, though we do talk of perfective and imperfective interpretations.
Aorist
There is no 'aorist' tense in English, though some languages, like Turkish for example, do have an aorist tense, as of course does Latin and Greek.
Perfect
The perfect is a past tense that is analytical rather than inflectional like the preterite tense: cf. "I have been to Bonn" (perfect) ~ "I went to Bonn" (preterite). The perfect tense can combine with the preterite ("I had been to Bonn") and present tense ("I have been to Bonn"), but can also occur in clauses without inflectional tense ("having been to Bonn").
Pluperfect
This is an old out-of-date term, now generally replaced by the term 'preterite perfect' (see 'perfect' above).
Note: some people call the 'preterite' the 'simple past tense'.