Creating a theme is simple and doesn't require any programming knowledge at all.
However you'll need to install Android Studio to build your theme.
1. Download the example theme from here or more advanced one here.
2. Extract and open theme with Android Studio.
3. Change AndroidManifest.xml with your unique package name and app name.
4. Change values.xml or put png files in drawable folder.
5. Build and deploy the theme.
Full API reference with valid values and file names
If you have any question - Contact email@example.com and we'll help you build your theme.