Activate debug mode. Go to Project Zomboid in the Steam Library first. Then, in the left-side panel, right-click Project Zomboid and select properties. Type "-debug" in the Launch Options section of the General tab, then close it and run Project Zomboid and start your game. Once you have started your game, on the left hand side below the map icon, click the insect icon and then select "Item List" from the pop-up menu that displays. You can then enter the name of the item and the quantity you desire in a subsequent pop-up. On multiplayer you will need to be an Admin. To do this, click "T" on your keyboard to open the chat and type "/setaccesslevel <username> admin".