I tried using it on Windows Chrome 23, but not going well. I get into creating screens, but can't for the life of me figure out how I can start drawing those sc

I tried using it on Windows Chrome 23, but not going well. I get into creating screens, but can't for the life of me figure out how I can start drawing those screens. I seemingly can only edit the name of the screen or delete it. Also, the page is too wide for my 1366x768. See http://imgur.com/kzIqN http://imgur.com/kzIqN