To manually add or edit the upstream and downstream cross-section linkages for an ResSim reach:
Select Reach: Drag the Geometry Editor window next to (or on top of) the ResSim main window. In the Geometry Editor, from the Connections tab, select the ResSim reach of interest (e.g., Yoakim Bridge). The selected element will be highlighted and zoomed into the map window schematic display area in the ResSim main window (e.g., Yoakim Bridge highlighted in yellow).