The Moodle page has been updated with some useful links to documentation and videos. Note the clear video from HRDNZ on uploading files.
Note that you can easily add mutiple files, simply create a folder of files on your computer.
Right click on your folder and select Send to – Compressed (zipped) folder.
On your Moodle course you can then add a file and select your zipped folder.
If you upload your file to a folder on Moodle you can choose to unzip the file.