: Use a sharp hobby knife (like an X-Acto) for clean cuts.

While there is no single file officially known as "GPM 557 USSR zip," this likely refers to a digital scan of a from the Polish publisher GPM (Grzegorz Pomorski Models) . GPM is well-known in the modeling community for detailed cardstock kits of vehicles and aircraft. About GPM Model 557

If you are looking for the official kit or replacement parts, the GPM Official Store is the primary source for their catalog. Many modelers also share tips and build threads for Soviet armor on forums like Papermodelers.com.

: Always test how parts fit together before applying glue. Where to Find Authentic Files