Does anyone have a tutorial on how to create these images in photoshop?

Thanks in advance from the newbie!!

Find (or take) an image of a can, box or what ever. In Photoshop use Free Transform to size and position the kids so the "fit". Set a hide all (black) mask on the layer with the kids then use a white paint brush to paint them into the container.

Or use the pen tool to make a selection of the area and add the mask to the layer to be added. Much faster, and more accurate that painting it in with the brush, in most cases.