The Add Menu is loaded when the button is selected from the New Project Menu.
To add a new arc, click . Define the start node by clicking <MiddleMouseButton>, or pressing <2>. Use <LeftMouseButton> or <1> to add vertices, and <MiddleMouseButton> or <2> to add the end node. Repeat the above process to add additional arcs. When finished, click <CTRL-RightMouseButton> or <9> to stop adding.
Tip: Attributes on the new arcs will be set so that the arc "does not exist" in the Base Network.
To delete the last arc added, click on the button. To set the snapping tolerances, use the Snap Tolerance Menu which is displayed along with the Add Menu.