Once you complete the first guest's check-in, you'll see this confirmation and then you can click on "Check in more guests". As long as their reservation(s) is linked to your reservation, they will appear...     You will go to a screen showing all linked guests. Your screen may look a little different since we are all checked in... Even after you check them in, you can always click on the icon on the upper-right to go back in and modify/change your info or boarding