Search sites like PaperToy.fr or Pinterest using the keywords "Puerto Papel Paper Toy PDF."
The episode features Matilda dealing with a "curse" involving a pipe cleaner that makes things disappear or change. [S1E8] Pipe Cleaner
If you are looking to build the paper model from this episode, you can find it through these official channels: Search sites like PaperToy
Visit the Paper Port / Puerto Papel official site to browse their "Descargables" (Downloads) section. [S1E8] Pipe Cleaner