Go to the free video hosting platform, in this case, Youtube, and choose a video
Go to the title below the youtube video and click the button entitled, 'share'
When you click on the button, embed should be the first option
Click on the embed button. You should get a screen that looks like this:
Copy the code from the screen by dragging your mouse over the text, right clicking and selecting 'copy'. What you are copying is known as the iframe code.
Go to the html document/webpage that you would like to embed the video in. Paste the copied code by clicking control and v or command and v on your keyboard. Place the code into a div and give it a class like so:
You should have a video now. Congratulations!