Websites like UnlockTool.online or GSM-Tools.net offer remote flashing. You pay a small fee ($5–$15), install their remote agent, and they flash the phone using their enterprise-grade Auth Files. This is the best route for non-technical users.
The method of using the file depends on the tool you are using. Tecno Bb2 Auth File
Not all flashing tools implement Auth file support equally. Here are the top performers: Websites like UnlockTool
The BB2 auth file is indispensable for several common repair scenarios: install their remote agent