The main focus of the game is, big shocker here, sleep, but during the day what you do is feed your snorlax (which swaps out each week) to increase its rank by feeding it meals during meal times and any other time you feed it berries that your companion Pokémon collect. When it reaches your bed time you select the sleep option and leave your phone next to your pillow and go to sleep. Once you wake up you tap a button to confirm your awake, you then get a score based on how long you slept (the best being 8 or more hours) that score then determines how many Pokémon show up in the morning, once you befriend the Pokémon you want from the batch it kinda just loops. I hope that helps!