Preparing a Theme to show up in the Theme Menu of the Admin Plugin

The Theme that I have developed does not show up in the Themes Menu of the Admin Plugin.

What steps do I have to take before my Theme is ready for the Admin Plugin ?

I think the only critical thing is to have a .yaml file. However, If you want it to show up properly, it needs to have a blueprint file, a PHP class, and also the appropriate thumbnails.

Just look at any other theme in the GPM, and ensure you have all the bits they do.

okay I have missed the PHP class, i am going to try it out !