+ How do I upload multiple documents?

The best way to to upload multiple documents is to create a .zip file.

1. Locate the file(s) or folder that you want to zip. Press and hold (or right-click) the file or folder, select (or point to) Send to, and then select Compressed (zipped) folder.
2. A new zipped folder with the same name is created in the same location. To rename it, press and hold (or right-click) the folder, select Rename, and then type the new name.

+ How do I upload a really large file?

The liftforward.com/docs page is made for the upload of large files, but if you're having trouble just create a .zip file (see instructions in the question above).