It's easy to tell a male from a female dog, just look at whether its genitals are on the belly or next to the butt. The one on the belly is a boy, as shown in the picture below, the one far away on the left is a male dog, and the one very close on the right is a female dog. Moreover, the belly of a male dog is relatively clean and not covered by hair. The female dog's genitals are relatively flat and there are several spots on her belly. Because these so-called spots will develop into the dog's breasts later.
You can also look at the urinating posture. The one who squats to urinate is a female dog, and the one who stands and raises one hind leg is a female dog. It's a male dog. Male dogs are obviously larger, stronger, more muscular, and have a more powerful feel, while female dogs are more docile.
