How to upload & embed a Youtube video
Go on youtube.com and click the "Create a video or post" button to upload a video
Drag the video file you want to upload into the video upload page
Give your video appropriate title, description, etc., click Done, and wait for the upload to complete
Once your video has uploaded, follow the link to its page and click Share
Choose "Embed" as your share type
Copy the iframe code and paste it into your HTML. You're Done!
Sample video used in this tutorial can be seen here: