Find birdseed at grocery, hardware, and pet stores. Mixed birdseed is fine, but black-oil sunflower seed is best. You might want an adult's help for a couple steps.
Remove the outside wrapper from the plastic bottle, rinse the bottle well, and turn it upside down to dry.
With a ruler, measure two inches up from the bottom and use the marker to draw a half-inch "X" to mark the spot. Then turn the bottle 90 degrees and measure five inches up from the bottom and draw another half-inch "X" to mark the spot. Then draw a one-inch-wide circle opposite both of the X marks, as shown.
This next step is an adult's job. Ask an adult to use the utility knife to slit the two X marks and cut out the one-inch circles.
Insert a wooden spoon handle through each of the cutout circles, then push handles through the X mark. The wooden spoons will act as a perch and also catch seeds that fall out.
The first part of this step is also an adult's job. Ask an adult to remove the cap and use the utility knife to poke a small hole in the top. Then take the screw eye and twist it into the center.
Attach a piece of twine to the screw eye and tie it tightly in a knot. The length of the twine will depend on the height of the branch or hanger you want to hang the feeder from.