Use Filters to find Videos, Playlists or Channels
Advanced Search Explained here
YouTube customizes your "start page" based on what it thinks you want to watch using your watch history, likes, your location and your subscriptions.
In your YouTube settings you can set notifications to send you emails about trending videos, videos from your subscriptions etc.
Create a YouTube Account
Go to Youtube, and then sign in using your Google Account. Hit the upload button and follow the prompts to get your channel up and running.
Search for Channels by Topic
Search for topics related to your teaching. Are there channels out there that look like they might be producing stuff you can use?
Start Subscribing!
Subscribe to excellent content (either my suggestions above, through search, or by browsing Youtube/edu
Check your Notification Settings
Get your settings just how you want them.