It's my understanding that it's like a commercial flight checkride and oral. I think on the oral it more in depth about systems. You may want to refresh on hydraulic/non-
hydraulic procedures and what each warning light means and corrective action. They may also ask you about flight and duty time limitations. If your company is larger than the Single Pilot or Single PIC operation then there is an operations manual that you should read and understand. Also, know what's in your Operations Specifications.
I do consulting for Part 135 operations and it's always getting more difficult to be in this business, that's why operations are moving towards fractionals.
Good Luck with your checkride and post some feedback