The short answer:

Provides options to test a SIM card temporarily or commit to a permanent network unlock.

: As this is unofficial software often hosted on file-sharing sites, always scan the download with antivirus software before running it.

But carrier locks restrict your choice of network. Most users consider it worth it. You can relock only by reflashing original carrier firmware.

: Ensure your modem drivers are installed. Close all other internet-related programs before starting the process. Identify IMEI