After the kids finish their ChatterPix, have them save it to the camera roll of their iPad by clicking this button:
It will export the ChatterPix to the iPad, then they'll get a little green checkmark when it's all done. Next, they'll open Seesaw and use the Camera Roll button to add it to Seesaw.
Once they click Camera Roll, they'll choose whatever folder is at the top (on the left hand side) and then find their ChatterPix from the right side once the folder opens. Have them look carefully - this can sometimes be tricky with ChatterPix because they'll have the photo they took to put into ChatterPix and then ChatterPix with their voice added. But often these look very similar. So remind them to select the last one and be sure they've chosen the one that's a video.