Assemble the attachment according to the manufacturer's instructions.
Unplug the mixer and ensure the mixer is turned off. You don't want the mixer to start unexpectedly at any time.
Open the cover for the attachment connector and loosen the attachment knob. Depending on your mixer model, you either lift the cover up, or remove it completely.
Insert the end of the attachment into the attachment connector on the head of the mixer. The attachment has a metal power shaft and a pin that must be aligned with the connector. The connector is a square shape and has a notch next to the attachment knob. The power shaft of the attachment fits into the square and the pin fits into the notch. You may have to rotate the attachment around to align it with the connector and notch.
Tighten the attachment knob.
Place a bowl or plate on the counter in a location under the attachment where it will catch the food as it exits the machine.
Plug in the mixer.
Start the mixer running at the speed recommended by the manufacturer. Different attachments require different speed settings. Use speed 2 for the can opener; speed 4 for the food grinder, slicer and shredder, pasta roller, and fruit and vegetable strainer; speed 6 for the citrus juicer; and, speed 10 for the pasta maker and grain mill.
Add food at the top of the attachment.
Use the supplied tool to push food into the attachment, if necessary.
Turn off the mixer when all food has been processed.