I don’t know its breed; what should I pay attention to in feeding?

The dog in the picture is a mixed-breed Teddy. Regardless of breed, care is similar. For diet, a puppy’s gut is immature and weak, so use puppy kibble fed in small frequent meals, and avoid human food to prevent pickiness and gut disease.

For vaccines and deworming, take it to the vet regularly; before vaccination, do not bathe it or expose it to pathogens outdoors.