Currently, you may only choose from the available list of modes within Modemaker for each product. You cannot build your own custom modes from scratch.
Available modes for each product differ, and in many cases these modes can be customized by flash frequency & output brightness.
Modemaker will allow you to add modes outside of your lights default mode list also, although some default modes may need to be removed in order to make room for new modes. Modemaker compatible lights only have so much memory available!