When you want to connect your device to the internet and have no connection available, you can create a hotspot with your phone.
Please follow these steps how you can create a hotspot on your Android device.
For iPhone users please refer to this link.
- Go to Settings > Tethering & portable hotspot > Set up Wi-Fi hotspot
- Give your Hotspot a name and choose if you want to use a password
- Connect your device to the hotspot you have generated