As this is essentially the same as adding a post I am going to refer you to that information.
The only difference is that you won’t see a place for adding tags or categories. That because pages have a different role to posts and therefore don’t get tagged or categorised in the same way.
You can however, [...]
Adding an image or any additional content is as simple as clicking on one of the links alongside the words Upload/Insert, just above this content box.
The icons in this order allow you to upload:
Images
Video
Audio
Media
Media is such things as documents, pdfs etc.
Click on the add an image button and you will see this:
Click on select file [...]
