In case it's hard to tell, but they have a big case with drawers and each drawer has a letter and then a bunch of objects that start with that letter. The children take a drawer to their work rug and they have apparently been trained to make a little song for each object, saying the name and then emphasizing the sound.
In this other work, it appears that there is a box of letters, and the kids have a picture with the word printed below. Then they have to make the work with the letters from the box. It's pretty cool, really.