Simply put if you want to let remote users have access to your My Cloud there are three basic ways *to accomplish the task. There are other methods of access but the following are the simple basic methods for remote access.
First: Go through the web portal MyCloud.com. this would involve creating a User account, assigning that User account to a Share (or folder), configuring that User account for remote access which then will generate an email that will allow the User to create a MyCloud.com account. From there the User uses the MyCloud portal to upload/download content from the My Cloud folders the User has permissions to access.
Second: Create a User account, assign them permissions to a Share, then configure the account so the User can use one of the WD mobile apps (for iOS or Android) or use the WD My Cloud Desktop software to gain remote access to the My Cloud to upload/download content.
Third: Enable the FTP server on the My Cloud, configure one’s router/gateway to port forward FTP to the My Cloud, create a User account, assign that User account to a Share, give the User account info (including password) to remote users and they can use any number of FTP client software (Filezilla is a popular one) to access the My Cloud remotely via the FTP server.
If you haven’t already done so read through the WD My Cloud User Manual. It will get you started with the basics of creating User accounts, assigning Users to Shares, the WD mobile apps, the WD My Cloud Desktop program, and enabling the FTP option.