You may follow these steps below:
1. Make sure the Bluetooth on your phone is switched on.
2. Tap "Bluetooth Audio" on the infotainment screen.
3. Tap the phone icon on the infotainment screen.
4. Copy the pairing code displayed on the infotainment screen.
You're paired!
Do note that not all phone models work for all Toyota Vios E's Bluetooth connections.