First of all, you need to know the tags! First tag you need to know is, < video > tag. without the spaces between the video. And also < source > tag. also without the spaces.
Here's a example of the code on how to use it.
As you can see there's nothing visible. Therefore, you have the Boonlean Attributes. Let's Move on to Step Two!
Second of all, you can use preload values, like auto, metadata, and none. But, main thing is to know is the Boonlean attributes, like autoplay, controls, loop, and muted.
Here's an example of the Boonlean Attribute.
First off, you need to have a external css file. Therefore, make a folder in your main folder, and call it css or anything you'd like.
Now, you got your folder, now make a file in it called "myfile.css" or anything you'd like! I named mine tutorial.css.
Now you have your CSS file, now you need to find a video on YouTube or any other service, and then click on the video, and hit share. Now you should see a text called "Embed" like in the picture.
Now you should see the iframe tag.
The third step is, now you can change some options, it's optional, but you can do it.
The fourth step is, now finally copy the iframe, and paste it into the editor.
Now, you have the final video, that's how to embed a video from youtube or any other services.
Below this text, is the video I used for this tutorial. I hope you enjoyed, and learned from my tutorial!