Self Check-In Codes

[Simon2574]

Hi, I would appreciate if someone that has self check-in to their properties could explain how it works. I saw that I need to enter my code in advance on my listing's page, but when and how do the guests receive the code? Is it a certain amount of hours before they arrive/ by their location or can I decide when to tell them? Will I be alerted once they received the message so that I can know that they're all set?
Thanks in advance!

[Gordon0]

@Simon2574 - the help page brings up these details: We won't show guests these instructions until 3 days before their check-in date. Instructions are saved to the guest’s phone and can be viewed even if the phone isn’t connected to the Internet. 

That said, having used SCI myself, I don't remember having all the detail so far in advance, but it's in black and white!