Confirm the type of video format it is and download it. The file will either be .mp4, .ogg, or .webm. After downloading it input the code in this style:
<...source src="https://youtu.be/aWzlQ2N6qqg" type="video/mpeg"...> <.../video...>
(When doing the actual code, remove the periods next to the brackets)
When you have the video you can adjust the height and width with these:
<...video width="320px" height="240px"...>
(When doing the actual code, remove the periods next to the brackets)
The first step is to go to youtube and select a video you like as shown below.
The next step is to click share and after a small tab pops up, then click embed.
The step is to click copy and then paste it into your html page.