Composite Material; missing 'Input' slot?

[helloimneil]

Wanted to explore the composite material and in referencing aoktar's Octane manual, I've hit something of a snag insomuch as that the created Octane Composite node does not have an 'Amount 2', 'Amount 3' slot in which to pipe in the created float nodes.
Present, however, are slots named 'Material 1 mask', 'Material 2 mask', etc.

Any ideas?

[daabomb101]

Material 2 mask corresponds to the same thing as the amount slot in a mix material. Hope that helps!