From Creatures Wikia
Basic operation of the tool is fundamentally the same as the agent injector, albeit with one more tool and a different item selection process. To operate the machine, turn it on with the blue flashing button, drop your item into the tray (the bin surrounded by rotating rings) and press the small, circular red button. The agent in the tray will be copied and re-injected. The remaining bars are exactly identical in all respects to those of the agent injector and are self explanatory.
Another feature of the replicator is its ability to create all the required parts of your newly-designed gadgets by replicating their blueprint. To do this, create your gadget by wiring its appropriate nodes together, use the context help to open a window about any one of your nodes, and press the button next to the red one in the top right. This should create a blue rectangular object. Drop this into the replicator and follow the standard process. All the parts are then injected for you-- isn't that handy?