This is the "Add Media" button.

This button allows you to upload four kinds of media. A video from YouTube, other video files, audio files, and other code.

Clicking on the "A Youtube Video" button will take you to this screen.

Here, you can copy and paste or type in the URL to your chosen YouTube video. Changing the width and height will adjust the size of the video within your content block.

Clicking on the "A video file" button will take you to this screen.

At the top, you have two options of where to upload your file from. "Upload a video file" will allow you to upload it directly from your computer. "Browse this website" will take you to the file browser on your website. Here is a link to the page that explains the file browser. File Browser

Below this is the size. Like the YouTube video, you can change the width and height. Under that are two toggles. The first is to "Show Player Controls" and the second is "Loop". Player controls are the buttons on the videos that allow you to fast forward, rewind, pause/play, etc. Loop makes the video automatically replay when its done.

The next option is similar to the first. This will allow you to chose an image to be the cover of the video. You can upload it directly from your computer or from the website. You can also upload an alternate video file under that. This should be the same video with a different file format, just in case the original video. is not supported by the browser. 

Clicking on the "An audio file" button will take you to this screen.

The options here are similar to the ones on the video file. You can upload an audio file directly from your computer or from the website. Underneath is a toggle that will make the audio file automatically restart once it finishes.

Clicking on the "Another website or some other imbed code" button will take you to this screen.

Here, you can type in a code to embed another website or media from another website.