UPDATED on 12th May 2018.
Learn more about Dark Net or Deep Web:
Beginners Guide to Deep Web or Dark Net.
Download Tor for Android
In order to use Tor to browse through the internet on your Android device you can either download Orweb Browser provided by "The Guardian Project" or simply use a Proxy Mobile add-on for Firefox(for Android)
Tor for Android has tons of customization in its Settings menu, which also included Tor Tethering to enable Tor Transparent Proxying for WIFI and USB Tethered Android Devices if you are planning to use your Android internet connection on other devices. Others include Node configuration, bridges, relays, reachable addresses, hidden service hosting etc.