When working with an MRTK project, most aspects of testing will work just like any other form of XR testing, with a few additional setup requirements.
Before utilizing GameDriver's MRTK support, the MRTK package must be obtained and extracted into either the game project's Asset folder, or alternatively into the GDIO folder in which the GameDriver agent is installed into the project. This archive file containing the MRTK package can be obtained from GameDriver support via email.
This setup process involves making changes to the 'MixedRealityToolkit' component, wherever that may be in your scene. While the exact location and configuration may vary depending on how your particular project is set up, the component should look like the following:
Under the 'Input' section of the component, open the dropdown labeled "Input Data Providers" and click "Add Data Provider".
From here you can select 'GDIOSimulationService' as well as configure the platforms you would like to support and other setup options depending on your project's needs.