The button maker in the shop is a "1 1/4" Badge-A-Matic" made by "Badge-A-Minit". If the Button Shells, Pinbacks, and plastic covers are all gone, more can by found from 3rd party providers for much less then Badge-A-Minit sells. Just make sure they say they fit Badge-A-Matic. USA Buttons is a good place to look.
1st step is to get art work. If you have specific art work you want turned into a button, use this template to help you make the correct size. The outside edge is what will be cut, the dotted line is what will be shown on the badge it's self. Media:125-button-layout.pdf
2nd the art work must be cut out. You will find in one of the button boxes and red circular cutter. Place the cutter so that the 4 white dots on the clear plastic part are touching the edge of template outline(or if you are cutting random images, that most of the image is inside these dots). Then using the handle, press down with even force and turn. It might take a few tries to get good at it.
3rd is putting all the parts into the Badge A Matic. 1st the pin back goes in with the zig zag facing up and the loopy side to the left. next in goes the shell with rounded side up, then the artwork with top of art work facing away from you, and finally the clear plastic piece.
4th is pressing the artwork and plastic around the shell. with the badge a matic set to setting 1, press down on handle until you hear it click. you do not need great force. the more force you use, the greater chance it will actually break the shell
5th is pressing the shell into the pin back. the pin back needs to be down inside the hole. If it stayed up with the shell, grab it and put it back in place. the move the lever to position 2 and genitally pull down on the handle. again, force is not required. you just have to pull down until the top and bottoms touch.
6th eject the button with the ejector tab in the back. if ejector tab does not push the button out, pull down on the handle while in position 2 again using a tad more force. ejector tab needs regular lubrication or else action will get very rough.