First mount the rotary attachment and plug it in. Make sure you turn the laser off before you do this. After that, you can switch on the laser.
Then apply a damp paper towel on the surface of the bottle and use a sponge or spray to moisten the towel. This will help prevent the glass from splintering and help you get a white engraving. Make sure there are no air bubbles or wrinkles.
Next put the bottle into the rotary attachment. It may be necessary to adjust the inclination angle to bring the engraving surface to a parallel position.