How does the specifc time selection work?

In lighting automation there is an option to select a specific time which presents sunrise or sunset then give the ability to select an offset. All this is used as an option instead of setting a time in hours and minutes. Is there some magic to invoke this dialog in the settings or is it just a lot of options in the smartapp? Is there an example app which uses this interface that has visible source code instead of it being hidden away like the lighting automation code?

You can see how the code works in the developer docs here. You can follow these docs to create your own smartapp in the programming language SnartThings uses. Its called groovy.

Word or warning. SmartThings is moving to a new developer environment, so I am not sure how long groovy will be available.

I saw that but wondered if there was a simple way to present the sort of user interface that can be found in the lighting automation smartapps.