How does the porting to Asda sim work?

Waiting for my number to port over to Asda sim so I can the port back to lebara as a new customer. Not ported to many times before so need clarification as to how the porting to Asda works. With Asda once my number is ported am I good to go or will I receive a message from Asda with settings that I need to update. It’s just that I’m currently waiting for my number to port to Asda and there is no number associated with my iMessage. I haven’t activated any settings for the Asda sim.