Need Help Adding a Note to WordPress Post

I’m trying to add a note box in my WordPress post like the one in this link – http://demo.herothemes.com/. (This is the theme I’m using). I can’t figure out how to make the note box appear in my post like it does in the demo. I can’t find documentation about it on my theme’s help pages. Does anyone know how I can create this box? The only post format currently available in my posts are Standard and Video.