Get a Saw or a Garden Saw, right click on it, and choose which limb to amputate. You can also drag n' drop your Saw item directly into the afflicted area to start cutting it off.

If you have a tourniquet, place it on the correct side to dampen the amount of damage you will take after you're done amputating the limb.

Keep in mind that if you amputate your upper arm, you won't be able to equip any prosthesis.

Cicatrization

You can check the cicatrization status of an amputated limb from your Health Panel. From time to time, you should clean your wounds with a bandage to help the cicatrization process. If your limb isn't completely cicatrized, you can still equip prosthetic limbs, but that can trigger random bleedings from that area.

Prosthesis

If you're missing a hand, you won't be able to do a lot of things, such as equipping two-handed weapons. With prosthetics limbs, you can fix that. There are two prosthesis type that can be crafted\found.

Hook Prosthesis
Arm Prosthesis

The main difference between the twos is that your actions will take longer with the Hook Prosthesis.

Multiplayer support

A player with a higher medical skill can help by doing the deed for you.

Credits


Pao	Developer
Mr. Bounty	Original developer
Chuckleberry Finn	Logo and Icon
dhert	Compatibility API
The Zomboid community as a whole	A lot of little things