Click the top edge of your monitor to open overview, bottom edge to open message tray. On touchscreens, simply swipe in from the top or bottom of the screen! Scroll along the right edge to switch workspaces.
Note: Binary files aren't shown on the web site. To see all files, please download the extension zipfile.
This extension is quite misleading - there's nothing touchscreen-specific or even "top bezel swipe" about it. It's rather "enter-and-leave the top bar quickly enough".