There are two ways to manually start a program:
1) go to Run Once program and load a program from the dropdown list
2) Go to the Program settings and click ‘Start this Program Now’ button.
To start one single zone, just click on the zone name and choose a run time.
User manual is at:
http://www.opensprinkler.com/support
How to obtain WUnderground API key is also in the support articles.