Nodes are the joints of the truss, which are assumed to be frictionless pins in the simple analysis we are considering. Defining the node locations is the first step in defining a truss model.
Choose Nodes... from the Model menu and this opens the Node Edit Dialog:
Click the add button to add the first node:
By default new nodes have position (0,0) and the node is displayed on the main window:
adding three more nodes and change their positions to (1,0), (1,1) and (0,1) by editing the positions and hiting <enter> in the text boxes to make the changes take effect, gives a Node Dialog display of
and the the main window looks like
The nodes are displayed in gray until they are connected by elements.
The next step is to Define a Material Property set.