Wooden Bridge Project

I have a project to do for Finite Element Method. I want to approach it using Revit/Dynamo, but I don’t know how to start and how to make it possible. I have to calculate this wooden foot bridge Ihttp://www.realwowz.net/2013/03/wooden-bridge.html

I would like to model it in Revit, but I never made such complex geometry. Do you have any advices how to tackle this problem ?