Bian is another Chinese name for Binance. The official download is at binance.com. Register via this secure link, download the APP here.
Multiple names: Bi-an, Coin-an, An-bi all refer to Binance.
Official address: binance.com. Verify HTTPS, professional design, company info in footer.
Android: Download APK (~100MB), enable unknown source, install.
iPhone: Overseas Apple ID required. Register at appleid.apple.com, select US/Japan.
Desktop: Windows (.exe) and Mac (.dmg) available.
Post-install: Register, KYC, Google Authenticator, anti-phishing code. Lite/Pro modes available.
Summary
The Bian exchange app official site is binance.com. Download from official channels and complete security setup.