The simplest way to load your My Cloud is to connect to a Gigabit router or switch, and use the Windows shares to copy your content over.
Note you can also use the WD desktop software, Make sure you connect to the device seen on your network.
In any of the cases above, you will use your internal network.
When you are remote, you can access over the INternet, using the WD My Cloud desktop software. You need to make sure you enable the user for remote access on the My Cloud as you set it up, create a password for the WDmycloud web site (wd2go.com). As you access the My Cloud this way, you will have first to enter the password of the web site, then the password of the device at home.
You should see the shares on your network. Make sure the drive has been set up with the same network as your computer (typically WORKGROUP). If you have set up users on the drive, the set up software will automatically create user shares, but your should see default shares like the public share, the timemachinebackup share, etc.
Don’t forget to go to setup.wd2go to setup the unit on your network.