Hey Ally!
Okay, so first things first; moving sprites. Do you see the buttons on the top of each post box? The button that looks like a photograph with a small green circle is the button to add an image. In order to insert a moving sprite, pick which one you want (must be the actual link and not a saved, still photo) and place it under the URL box. Then, size the sprite using the length and width sizers and press "Insert".
As for normal words into links, this is a lot easier. Do you see the button at the top that looks like a chain link with a small green circle at the bottom right? If you click on that, two separate text boxes appear. In the top one, enter the link location that you want people to be redirected to when they click on it. In the bottom box, enter the text that you want displayed.
Hope this helped!