Hov captions

I recently made a project where symbols are buttons and hovering over them brings up a pop up description. Although i do not know how to affect the text in the boxes and am only seeing half of an oversized W. I used the old hover captions tutorial on the site and made a few mistakes but ended up with what i wanted it to look like. If someone could explain how to effect text size, font and other things in a hover caption that would be greatly appreciated also i need it to wrap around to the next line. Keep in mind i am new to this.