Right-click on the desktop and choose Screen Resolution
then, using a paint program, make up a Lock Screen
with the appropriate size (example: 1280 x 960)
Then save your new Lock Screen in some picture folder.
Now bring up the Charms Window (that's Windows+c)
You can also change your Account picture
and right-click some icon (Example: desktop)
(Example: Movie Maker pinned to Taskbar or Start Screen)
My Start Screen looks like this
and right-click the icon for some App (Example: AVS4YOU)
My Desktop looks like this (with most shortcuts in folders).
Open the Control Panel (using Windows+x) and select Hardware and Sound
then select Manage audio devices
then pick the HDMI device (Example: SAMSUNG)