My first form created last year and largely followed the tutorials. The T&Cs, Attachments and Authorised Manager fields are required.
Also only allowed one employee to make the claim. This can be done via control settings for the Employee field, under Advanced, and set Maximum Entities to '1'.
Once form submitted, a simple workflow is initiated and using State Machine, checks if the Supervisor field is empty and routes to appropriate person to approve claim. Due to our work environment, Managers may not have an immediate Supervisor for approval first. Therefore claim goes straight to the approving manager.