Postage printer toner swap is significantly different than other models and not intuitive. To swap most of the printer's hardware parts:
1. Select settings at the top right.
2. At the bottom of that screen (will appear slightly grey as if non-clickable, but just needs to scroll down) select Envelope Printer Management.
3. From here it will open a page with multiple buttons that will make the printer release the lock on the hardware pieces. You cannot remove the toner without first selecting it from this menu.
The manual has been put in the center-right drawer beneath the device.
The toner is in the box with many items in the bottom-left cupboard. Toner is deceptively small but in little rectangular boxes.