How to connect pins with ratsnest connection after netlist transfer in Proteus ARES
try using the ares auto-router it should connect them for you. if this fails then you can manually add a track between the two pins as folows.
select the manual route icon, choose the top layer, left click on pin13 to start manual routing mode, left click anywhere you want the route to go, then left click on pin 4, then right click on pin 4 to end manual routing. a track should be placed between the two pins following the route you traced.