Always right-click on the .001 file. The software will automatically detect .002 , .003 , and the rest of the sequence to reassemble the original file.
Splitting files into parts like .003 is common for bypassing file size limits on cloud storage or ensuring that if a download fails, you only have to restart one small segment rather than a 50GB behemoth.
Double-check that all files have the exact same name prefix ( TPI_L.7z ). If one is named differently, 7-Zip won't recognize it as part of the set. Why Split Files?
Blog Post: Mastering Multi-Part Archives: Dealing with .7z.003 Files