Hi there, I would suggest you start by first trying to generate a workspace using this as a rough guide: https://safe-software.gitbooks.io/introduction-to-fme-desktop/content/2.translations/2.02.generate-workspace.html

The generated workspace might look a bit crazy but its a good place to start. Give it a test to see if it generates the shapefile(s) you want

Here is some more information about how you can work with GML in FME: https://knowledge.safe.com/articles/888/reading-xmlgml.html it might give you some tips on troubleshooting.

It is important to remember that a shapefile can only support one geometry type (points, lines, or polygons etc) so splitting out the geometry types with a GeometryFilter will probably be important.

Good luck!

Thanks very much Matt, I'll give this a go.