Pick up the pom pom maker. Open one side of it (both pieces) and begin wrapping the yarn as shown (while holding one of the yarn). You're going to keep wrapping the yarn until you have completely filled one side of the tool, including filling the "U" shape with yarn.
When you are finished wrapping one side, close it and feed the yarn over to the other side as shown below. You're going to undo the other side of the pom pom maker, and wrap the yarn just as you did. Then you will close the tool.
Use the scissors to cut the yarn on each side of the pom pom maker, while still keeping it closed.
Cut a scrap piece of yarn, and tie it around the center of the tool tightly. You're going to make a knot by double tying. You want to make sure it's tight enough so that when you remove the pom pom, it doesn't come apart. You don't need to pull so tight that you break the yarn, but you do need to make it snug.
Open both ends of the tool and pull apart to remove the pom pom.
The pompom will come out very shaggy, so you'll want to trim it up with the scissors, plus the excess yarn from tying.
Repeat the process, making six pompoms with each color except red. You'll make seven of those.
Make a heart template that fits your red pom poms. Draw the template on the thin cardboard and cut out with scissors.
Hold one red pom pom in your hand and smooth the yarn out from the center. Place the template down and cut the heart shape with scissors..
Repeat with each red pom pom until you have all the hearts you want.
Thread the yarn onto the tapestry needle, then thread the pom poms onto the garland through the centers. Start with a heart, then rotate through the colors.
Hang the garland. Space the pom poms out to desired length apart.