Each project has a number of nodes which are represented in network drawings by icons. To add a new location to a network (and therefore to all networks in the current project) select Networks | Add node from the main menu (this command is also available if you right click on the network drawing).
The cursor will change from an arrow to a crosshair. Click with the left mouse button on the drawing at the position where the new node should appear.
The Add Node Dialogue Box will appear, and you should enter details of the new node into this box.
See also