[FEAT] Create specification document for variables to be passed to DART

[aaronjridley]

Is your feature request related to a problem? Please describe. In order to pass variables to DART, we need to fully describe them.

Describe the solution you'd like Need to create a specification document and maybe sample code to provide an example. This actually should be done anyways, so that developers can know how to do things.

Describe alternatives you've considered I am not sure if we should just create some well documented source code to do this, or a document that outlines it. Maybe both.

Additional context N/A