It’s a good idea to keep the sound on , as it will beep at you for attention. When it has dropped one heart it will need to be disciplined. Don’t play with him or give him meals, first discipline your tama before taking care of it. So discipline him every times he calls for it. After the final time you discipline it in this stage it will get sick soon after, this tells you that he will change in the next 30 hours. Now you need to take perfect care of your tama to get Mametchi/Mimitchi. If you fail to do so you may end up with Ginjirotchi/Pochitchi.