NASA and USGS (United States Geological Survey) publish magnetic anomaly maps for entire regions. These show where large iron deposits, meteorites, or sunken ferrous objects might exist.
If you still want to try it:
A: Those videos are fabricated. Scammers use CGI, fake screenshots, or simply point their phone at a metal object and pretend the beep came from a satellite. They make money from views and link clicks to malware APKs. Satellite Nasa Metal Scan Apk App Download For Android