The content you are looking for, , likely refers to the Pastel Room MMD Stage created by MonsterShinkai on Patreon .
The asset typically functions within the MMD physics engine. It is generally distributed as a compressed archive containing: monstershinkaipastelroommmd1var new
Locate the by MonsterShinkai in your list of scenes and click Load . Adding Characters : Add an "Atom" (Person) to the scene. The content you are looking for, , likely