Dear Jacob,
Unfortunately, we don’t have step-by-step instructions for starting with FAST. It may be helpful to review the presentations and sample models/simulations that were presented at our last modeling workshop. These are available for FAST v8.08 (not quite the newest version, but I don’t have newer materials that are so comprehensive) in my Sep 15, 2014 post in the forum topic found here: Modeling Workshops. After that, I suggest that you study the various user’s guides and theory manuals.
Here are my answers to your direct questions:
See the “FAST v8 Input and Output Files” section of the FAST v8 ReadMe file: wind.nrel.gov/nwtc/docs/README_FAST8.pdf.
From the InflowWind module. See the InflowWind User’s Guide for more information: wind.nrel.gov/nwtc/docs/InflowWind_Manual.pdf.
The structural properties are specified in ElastoDyn tower input file, but are given in terms of mass per unit length and sectional bending stiffness in the fore-aft and side-to-side directions instead of in terms of geometry and material properties.
See the “FAST v8 Input and Output Files” section of the FAST v8 ReadMe file linked above.
Best regards,