KITCHEN DISPLAY fast food

Hi. I need to customise my Kitchen and Customer display screens. Its a takeaway fast food so there are no bills whatsoever. If the cashier rings up the items and settles them there and there but i need to still keep the ticket open in the kitchen track and customer screens only to be closed when delivered on the customer track screen. Your help would be greatly appreciated.

Thank you @QMcKay will update if i face any challenges

Hi guys. I have 2 issues. How do i update a task as completed and the other thing, can i use order number instead of long unique ID?