To sign pen, simply mimic writing something with a pen (or any other writing utensil) on a flat surface. Hold out your non-dominant hand flat, with your palm facing up, then pretend writing on it with your dominant hand formed as if grasping a pen.
Teach your toddler the crayon sign when they have developed the ability to grasp at objects and are ready to get creative with a coloring book.
Use the crayon flash card in conjunction with other arts and crafts flash cards. These will equip your toddler for creative self-expression.