New Pokémon Snap is a pretty open-ended game, unlike most Pokémon games out there, where your goal is to take pictures of Pokémon, build up your score, and continue exploring new areas.
Although this walkthrough is not necessarily designed (at least not yet) to tell you how to get perfect pictures of every Pokémon, it should at least give you some general tips for taking enough photos of Pokémon to advance through the game and reach the credits.
(work in progress)