When do I start infant bits of intelligence?

I have all these black silouette cards we made while I was pg, from the How smart is your baby book, and am not sure when to start using them. So far we’re doing b&w checkerboards and other black and white things.

You can start them at birth and use them until 4 months. Place them around your baby in the bed, changing table, tummy time, etc. You can also hold them up and let your baby look at them. Once your baby can follow objects you can slowly move the cards around and let him/her follow the image.

I guess I’ll do that. The book says to show one picture 10 times a day, a different picture a day, and then repeat the same 7 the next week or something like that. There’s so much to keep track of and remember to do! I couldn’t really figure out when I’m supposed to start doing it so I guess I’ll just start now!