Question

we went to a rocky beach. change into past perfect tense

Answer 1

PAST PERFECT TENSE

◆We had gone to a rocky beach.
(by using the V3 form of the verb)

Answer 2

We went to a rocky beach.

Given sentence is in simple past or past Indefinite tense.

Rule of past Indefinite tense is :-
Sub + verb 2nd + obj

Rule of past perfect tense is :-

Sub + had + verb 3rd + obj.

Here, verb 2nd = went.

Verb 3rd = Gone.

Sub = We

Obj = to a rocky beach.

So your answer is :-

We had gone to a rocky beach.