Nodes are displayed as gray boxes in the Work Area. Each node has different input and output channels depending on the type.
All materials have one Root node (marked with a thicker border) to which all nodes must be connected (either directly or through other nodes) to have effect on the material.
Channel connections are made by clicking on an output channel and dragging and releasing directly onto an input channel or onto the node itself. When it is released onto the node, a context menu will show all the available channel options. Once a connection is made, a blue line will appear connecting the 2 nodes. Right click the line to remove or disable the connection.
A disabled connection will be displayed as a grey dashed line. If you select a connection, it will turn light blue.