https://f95zone.to/threads/little-sister-v1-2-master-wuju.45362/
All you do in this game is taking naps - at least it was like that last time I played it. The only way to forward time was to click on the bed.
And since the game lacks any hints, you basically: take a nap, check all rooms, take a nap, check all rooms, take a nap, check all rooms, click a girl, take a nap. check all rooms, ... at some point repeat that until friday when only at one specific time of the week a tiny bottle of pills spawns. After that take a nap, check all rooms, take a nap, ...