Kevin,
Attach your drawing here. It must be less than 1 meg though. Someone will help.
Build it and they will come...
Long story short... add a MarkPoint to the Ditch (Generic Tab), add a LinkToMarkedPoint (names of both must match), add your sidewalk and last grading... the assembly is ready.
Need more help? I'll be around but you could watch the "Corridor Modelling—Using "Marked Points"
Recorded: December 8, 2006" webcast for clarification.
Happy Modeling,
John