A Max Creation Graph encodes a computation. It does so by defining a data flow: Data is input to the graph, flows through nodes that manipulate it, and emerges from an output node.
Nodes in the graph are instances of inputs, outputs, operators, or constant values. Wires between nodes direct the flow of data, moving from left to right.
Data flows from left to right.
To connect one node's output to the input of another, the data type of the two connectors has to be compatible: integers (whole numbers) for simple counts, three-value vectors for location in 3D space or for colors, Booleans for true/false values, and so on.
A graph must have one or more inputs or constant values on the left, and a single output on the right. (If a node in the graph is not eventually connected to the output node, that node is not evaluated.)
If you are making the graph into a compound (.maxcompound), then it must have at least one input on the left, and its output must be an Outputs 
Output: Compound node. Use Edit Edit Graph Properties to specify the Category in which the compound will appear on the list of Available Nodes/Operators.