For those of you wishing to change your background, the following will (I think) allow you to select one of the three now available. You may have to look around some for the buttons as they are in different locations on each Theme.
Starting out from scratch, open the board and find the home button. Click on it. Nothing really should happen.
Then find profile and click on it.
Then click on modify profile
Then find and click on Look and Layout Preferences
Edit profile screen should then come up and show your current Theme.
Click on Change.
Then select the theme you want to try.
Then click on use this theme.
That should be it. You should then go back to home and be in the new theme.
WOW. Would you believe I typed all this without a typing error. Sure is nice to have the Google spell check to verify this though. LOL
Thanks for the excellent explanation Richard.