Because .7z files can contain executable scripts or malware, use a "sandboxed" approach: Use 7-Zip or WinRAR.
If you aren't 100% sure about the source, upload the file to VirusTotal . It will scan the archive against 70+ antivirus engines to ensure it's not a "Trojan" disguised as a project file. LoOnly_Po-008.7z
Knowing the source website or the software it's intended for would help me give you a much more specific guide. Because
Is it part of a segmented download (e.g., part 8 of a larger set)? 2. Safe Extraction LoOnly_Po-008.7z