The easiest way to start finding more channels is to browse through Awasu's channel packs. These are sets of channels that have been hand-picked for their high-quality, interesting and useful information.
Choose the option from the main menu.
Then browse through the packs and their channels and subscribe to the ones that you are interested in.
Awasu's Getting Started page links to resources to help you find more channels.
You can also use the Syndic8 plugin to look for more channels.