MyCloud and Public Access

The first time, your friends will have to go through wd2go.com to map the share to a drive on their machine. Then they will be able to access through that mapped share.

http://community.wd.com/t5/WD-My-Cloud/ACCESS-FILES-FROM-MY-CLOUD-OTHER-THAN-THROUGH-APP-OR-SOFTWARE/td-p/684811

Alternatively, you could set up FTP access to your NAS. YOu will need to open/forward the FTP ports to your NAS