- Log into your YouTube Account.
- Click the little arrow at the lop left then click “My Channel.”
- Click on “Edit Channel Navigation” at the right center of the dashboard.
- Enable Browse.
- Click Save
- Click “For New Visitors”
- Choose Channel Trailer
Choose the video you want to be your trailer and then click save.
That is it!
Here is a video which shows you live how to do it on YouTube.