These are usually uploaded alongside the .rar files by the original poster. Check the same source (forum, Usenet group, or cloud drive) where you found the RAR.

If you are trying to "fix" or "complete" a set of archive parts where part02 might be missing or corrupted, you actually need a (Parchive).

Based on the filename structure, this typically refers to one of the following: 📄 1. PAR2 Recovery Volume

Do you know the or source where this file was posted?

If you are unable to open the archive, here is the most likely reality:

In some sharing communities, a "paper" refers to a text file or image (often called a "proof" or "nfo") that contains: The for the RAR. The source of the file.

If WinRAR or 7-Zip says "Checksum error," you need the Recovery Record if the creator included one. Open the file in WinRAR and press Alt+R to attempt a repair. Could you clarify: Are you getting an error message when trying to open it?

You cannot open .part02.rar by itself. You must have all parts (part01, part02, part03, etc.) in the same folder.