@quangqui007 Your baby will not act satisfied or full until they are like 5 months old. You ask what I did in the early days and if you follow this step by step plan you should be ok and baby will be well fed.
-get all your favorite snacks
-get all your favorite drinks
-assemble these near your comfy spot
-pick a good tv show
-hold and feed baby. Eat snacks. Drink drinks. Order DoorDash
-watch movies and shows. Beware of hormones
and shows involving babies coming to harm.
-shower when you can. Accept that it won't be much
-sleep when you can. Accept that it won't be much.
-if you keep in mind that your only job at the moment is to convert calories to breast milk and give to baby, and ignore the feeding times they tell you, and that no other task is more important, you can relax and just sit and feed baby.
You'll come out on the other side soon. Baby will feed, be full, and go off to play. But these are early days, just cuddle and enjoy it ... and the milk will flow.