You will not be able to understand this in only 30 minutes
Read the complete thread and try the several examples you can find there to learn how to work with the extension
See also this tutorial, which uses itoo Battery checker reminding you to unplug when fully charged
Then try to put some blocks together using the extension for your task
And if you got stuck, then ask in the itoo thread and provide a screenshot of what you tried there
Taifun