Craft paper-preferably red/pink/white
Cut the cardboard shaped as a tree and craft paper into different size hearts . Make all the cut outs before you sit with the kids specially if they are too young to use the scissors themselves.
Ask the kids to color the cardboard tree green, use crayons or paint.
Keep all the different hearts in a bowl and let the kids stick the hearts onto the tree.
You can also use small form hearts and glitters.
Mostly let the kids have fun its Valentine's Day -spread the love and enjoy the moment with your kids