The file upload functionality has been incorporated into UE 4. You need to have the form created then apply the upload server behavior. Within the upload server behaviors you can choose to rename the file that is uploaded, you could name it after the user or use some other identifier for the user to rename the file.
When you apply the upload server behavior you will have the upload bindings available to you. This will contain all of the info about the uploaded file including the name and location of where it was uploaded.
If you are having trouble getting the upload to occur you should go to the bindings and expand the Upload group then drag and drop the debug info onto the page. When you test the page out if the upload fails you should be able to see the details for the upload and any errors that occurred.
You can also find some How To's and additional info in the FAQ area on the UE support page here: