Kinda new to SU, and just updated to SU2015. How do I import 2D vector files so I can extrude and modify those 2D shapes?
Pro has quite a selection of import options.
Make does not.
But you might check http://extensions.sketchup.com and do a search for “import” to see what 3rd party importers are available.
Many of the available vector file import formats can be used to import 2D line data into SketchUp. DWG and DXF are the most common. SketchUp has no 2D-specific import function, it just imports the geometry in the file just as it is. If your shapes are in another format (like Illustrator files) you should use a compatible application to convert them into DWG or DXF.
SketchUp Pro and Make import and export Collada (DAE) files.
See this page: SketchUp File Exchange Features