How should I set up my External drives

I have a MyCloud, Easystore portable and My Passport Wireless Pro.
I need to know in what order i should set these up. Since I don’t have enough storage on computer to store all my pics and documents, I need to use 1 as main storage drive to, then one of the drives for back up or sync and lastly extra just in case.
Any advice would be greatly appreciated.


To set up the WD My Cloud device, follow:

Now, map the network drive:

For, NAS to USB Backup: