As you work with your net, you may want to add or remove nodes from a previously created node-set. Unlike adding and removing nodes from your Bayes net (which could affect the cpts), adding and removing nodes from a node-set will only affect the categorization of the node(s) within the net.
Adding: Select the node(s) you wish to add to the set, choose Modify → Add Nodes to Set, and click on the name of the desired node-set, or click on Enter and type in the name. Alternately, you can select one or multiple nodes, right-click on the selection and choose Add To Nodeset.
If you right-click an unselected node, the menu will just contain Nodeset instead of Add To Nodeset, Remove From Nodeset and Set Nodeset, which allows you to toggle whether or not the node clicked-on is in the nodeset you choose.
Removing: Select the node(s) you wish to remove from the set, choose Modify → Remove From NodeSet, and click on the name of the desired node-set, or click on Enter and type in the name.
Alternately, you can use right-clicking to remove them
in a manner similar to that described above for adding.