Take a cardboard of a size depending on your space and how much room you want for the butterflies. Cut the shorter flaps so that things clear out, and there are no obstructions in your view to the inside of the box.
Cut out the front and back of the box. You will fit a transparent screen here so that you can look inside the box. Leave an inch of cardboard on both the sides so that it is easier to paste the screen like shown in the picture.
The screen should be larger than the hole. Put the screen over the hole and tape it down firmly.
It is time to make the door. Draw a square on one side and cut it out on three sides, leaving the fourth intact. The fourth will act as hinge. The door will allow you to take things in and out of the box.
The box is ready. You can decorate it and make it look more attractive by painting in bright colors. Draw butterflies and floral patterns on it. Place some twigs and branches in the box for the caterpillars to climb. Hang the box somewhere in the open which has a roof and so is protected from rain.