If you don't have dumbbells at home, I suggest you use the following methods:

1 Do the most basic push-ups first, and add one every day until you can do 20 (the movements must be standard).

If you want to grow muscles, you must increase your strength (this is the only way to grow muscles). When you can reach 20, you can put some books in your backpack. You may only be able to do a few at first, but as long as you persist, you can gradually increase it to 20 in the method 1.

Now you can do deep push-ups. First put your hands on two stools (stools are where you usually do push-ups) and your feet on the bed. When you do this, you should lower your body below the height of two stools. Deep push-ups can better exercise pectoralis major.