Basically you can’t open your phone until the same time every day if you want credit for the km you’ve walked. So say one night you work till 2:30 with your phone in your pocket and when you get out, you open it at 2:35am. The next night, you can’t open it until 2:35am if you want candy from your walking that night. This is if you maxed out the previous night at 42km. If you got less the previous night, if you open it early you’ll just receive the remainder of candy that was left.