You never (well hardly ever) need to use a command button in PPT. In show mode normal shapes work and comand button don't work in edit mode anyway.

To see the code

Got to the VBE

Make sure project Explorer is showing (Ctrl R if not)

Find frmPrinters and RIGHT click > Show Code

You will see the code that runs when the form opens, closes or the OK button is pressed.

The code to open the form (when the shape is clicked) and the print code are in Module 1