I have found a powershell script to upload multiple files to a document library in SharePoint 2010 however I am using the 2013 version. Would this still work?
Link to script : http://www.spfileupload.codeplex.com/
This is a great script to add the files and fill in the columns of the document library with extra metadata i provide in a XML file. I hope there are other ways to do this in SP2013