To sign mommy, extend and spread your fingers apart on your dominant hand. With your pinkie facing forward, tap your thumb on your chin. The hand sign for mommy is the same as the hand sign for daddy, but signed lower on the face.
Traditionally, it is said that male signs are above the nose or around the forehead, because you can imagine a man tipping his hat to greet a woman. On the other hand, the female sign is below the nose, or around the chin area, because that's where women used to tie their bonnets securely around their head.
Mommy is a great starter sign and will likely be one of the first that your baby learns. Make the sign every time you approach your baby. If your baby is fussing and calling for you, make the mommy sign and give her a cheery smile, saying, "Hey, Baby! It's Mommy."
I would not use the mommy flash card to teach a baby. Instead, teach the baby the mommy sign by using the actual mom! If you do want to use the flash card, try and get a picture of the baby’s actual mommy to replace this generic picture.