How to Use 테니까 and 텐데 | Live Class Abridged

When I was first learning Korean, I couldn't tell the difference between 테니까 and 니까, or 텐데 and 데. I could understand it, and I knew which types of sentences it commonly appeared in (from hearing others use it), but I couldn't understand the difference or usage enough in order to use them correctly myself.

This is the abridged form of a live stream I did early this year about how to use 테니까 and 텐데. The full live stream was over 2 hours, but this video is only 13 minutes. If the video moves too quickly, consider watching the full live stream instead (or pausing this video).