Function node can be used to call Functions Sources.
Custom functions can be created using Function containers. Same Function container can be called in multiple places.
To create functions, you'll need to create and name a Container, and set it's type to Function Source.
You can define multiple inputs & outputs for the Function source in the Advanced properties. These inputs & outputs will show up in the Function node once the source is selected.
|Enable or disable the node, disabled nodes will not do anything
|Defines the function the Function node will call. Function source needs to be named to be visible in the Set menu.
|Defines the container Type. Use Function Source for Functions.
|Defines if the Function Source is Global or Local.
|Inputs and Outputs can be defined here.
Here's a link to the hype that shows how to implement and use the Function node: