The summary panel gives you a synthetic view of the properties currently assigned to Work Flow nodes belonging to one of three types: Input Variable, Output Variable, and Transfer Variable. In the summary panel there is a separate tab for each of these node types, and within each tab there is a table with a row for each node in the Work Flow that belongs to that node type.
There are two good reaons for using the summary panel. First, through the summary panel you can make changes to a large number of node parameters more quickly than if you had to open each node properties dialog and make the changes there. Second, the summary panel provides an order for the nodes, and this is the order used to arrange the values in the Designs Database. You can change this order by reordering the rows in the summary table (through the summary table contextual menu).
Of course, each node type has a different set of properties; accordingly, each tab in the summary panel is different. However, the parameters for each node type are the same that you can find in the node properties dialog, which we have already described elsewhere.