Tool Input: Signal
The Tool Input: Signal generates a button which sends a True value only for that evaluation of the graph, and remains False otherwise. When used with an If node and an Ignore First to control the flow of execution, a signal can be used to trigger the creation of node instances in the scene.
Note: The Clone as Instance in World Space compound is provided in the MCG 2018 sample pack, along with the MCG_Samples_Stamper tool (seen above).