answered and said

"said." Peter is not responding to a question.

it is good for us to be here

It is not clear whether "us" refers only to Peter, James, and John, or if it refers to everyone there, including Jesus, Elijah, and Moses. If you can translate so that both options are possible, do so. (See: rc://en/ta/man/translate/figs-exclusive and rc://en/ta/man/translate/figs-inclusive)