Alternatively, the user might be referring to a mod. If so, they would need to install it in the game's mod directory, but that depends on the game's modding support.
Do you have the of this archive saved in the same folder? poppyplaytimechapters2v25062023part3rar work
: Poppy Playtime Chapter 1 is actually free-to-play, and the full chapters are available legally via Steam or the official Mob Entertainment store. Alternatively, the user might be referring to a mod