You will notice the sidebar on the right of your screen. This allows you to attach media (videos, images etc) and notes to nodes in your map. It can be temporarily hidden, for more space working with your mind map, by clicking the full screen icon in the top toolbar.
To add notes to a node, simply click on to text area and start typing. As with everything you do on Wisdomap, your notes are automatically saved every few seconds as you type.
To add media to a node, click the plus button next the the "Media" heading. From the drop down menu, select the type of media. For example, to add a YouTube video, select "Video" and enter the video's URL. To delete a media item, click the minus sign next to the "Media" heading, then select the item to delete.