Appsheet workflow

I want to make a Inspection App. I have tried to sketch the flowchart of my app. I have done the dependent dropdown but cannot populate a list based on reference value in two columns Trade & Activity

Activity=Steel fixing
Status = “Passed”-------> Create workflow for pdf and email
Activity=Steel fixing
Populate the list of Issues that I have created in the Issue table for Trade=“Civil” & Activity=“Steel fixing” in a dropdown.
Create workflow and sent notification to the responsible person by Whaatsapp.

  1. It has to lookup values in two cells and if either of them is blank,a error message to be displayed to fill all fields.
  2. The inspection has to be assigned to a manager for final approval.My status will remain open till the approval process is not my manager.