In this recipe, you created a new Shader Graph that had several connected nodes. The output(s) of one node becomes the input(s) of another node.
You created publicly exposed properties for Color and Texture using the Shader Graph Blackboard and introduced those properties as inputs in your Shader Graph. By publicly exposing these properties, you allow them to be edited via the Inspector window when a Material that's been assigned to a Shader Graph is selected.
You used a Sample Texture 2D node to convert the 2D Texture image into RBG values suitable for the Albedo input for the PBR Master node.
You then created a Fresnel Effect node and combined this, via a Multiply node, with the publicly exposed Color property, sending the output into the Emission input of the PBR Master node. Multiply nodes can be used to combine different elements of a Shader Graph.
To apply a Shader Graph to a GameObject in a scene, you needed to create a Material asset file named...