The best method seems to be holy texts from so long ago that the origins are hazy at best. It’s one reason it’s hard to believe that Mormonism took off so well; Joseph Smith’s personal foibles are still well recorded.
From a philosophical perspective, "He Is There And He Is Not Silent" by Francis Schaeffer is solid. It's simple, but very deep.
(Smith's life is thoroughly, unflinchingly documented: https://www.josephsmithpapers.org/ ).
(Thoughtful comments appreciated with any downvotes.)