The story in LittleBigPlanet 4 is considerably extensive and uses "planets", "chapters", "sections", and "levels" to categorize all of the levels. There are 10 different planets and bosses you can visit, each of which having 4 sections (each essentially representing a continent of the planet). In each section, there are 3 chapters. These chapters take place in a certain part of the section. Within each chapter, there are 4 levels. This means there is a total of 1,400 levels (plus several ungrouped levels)!
Imagination is the first level. It does not fall under any planet or category. In the game's files, it is given the rudimentary name of "imagination.lbplvl", seeing it was made so early in development and a format for the name of levels was not made yet. It serves as an introduction level, and once completed, is impossible to replay without hacking.
Main page: LittleBigPlanet 4/Story/Imagination
The first real level. The level Imagination will seamlessly transition to this level. It is also impossible to replay. It is fairly long and introduces Redwick, Bluewick, and their starship. It is named "starship-c00-s00-lvl00.lbplvl", and opening the start menu displays its name as "nope" as a placeholder, and its level icon is shown as the "NO" meme over a white background (you're not able to open the start menu at the time this level can be played, but this displays through hacking).
Main page: LittleBigPlanet 4/Story/Starship
Armonioso is the first planet. Its sections greatly contrast each other: one section is an a forest section, one is a urban section, another a futuristic section, and one section set atop a rainbow and made of clouds.
A forest theme.
A city theme.
A futuristic theme.
A land set in the sky with abstract and psychedelic designs.
yarnia is the second planet. Its sections greatly contrast each other: one section is an ghost section, another a medieval section, one is a fairy tale section, and one section set in a underwater city with catfish.
A haunted theme.
A medieval theme.
luna sun town
A fairy tale theme.
A underwater city theme.