A channel is a horizontal track that's similar to a layer in an image editing program: higher channels are displayed in front of lower ones.
Within each channel, you can create one or more strips, which contain either a segment of video content (a rendered scene, an external video file...) or an effect (color blending, blurring...). The X axis represents time, so the further a strip is placed to the right, the later it will play in the final video.
While a channel can contain multiple strips, they can't overlap each other. If you want two strips to play at the same time, you need to place them in different channels.
The Channel region sits on the left side of the editor and contains the channel properties listed below. Its visibility can be toggled with.
The name of the channel. Double-click to change.
- Mute Channel
Disable the entire channel so that none of its strips can be seen (or heard) in the final video. Note that you can also mute individual strips.
- Lock Channel
Lock the entire channel to protect all its strips against accidental changes. Note that you can also lock individual strips.