I don’t believe you are reading anything because it is there!!! What WD Device do you own? Is it a second generation WDMYCLOUD?
Look at the apps and see what is available.
GoodSync
Automatically backup or synchronize data stored on your NAS device to any destination including other NAS devices, PC, Mac, servers, or cloud storage. GoodSync is using block-level data transfer and works faster than Windows …More
If you don’t know how to do any of this, do you have a Best Buy nearby? Call the Geek Squad or at Apple Stores check with the geniuses. They may charge you though for their time.
What specific My Cloud model do you have? As the following WD Support Knowledge Base Article indicates, the third party Dropbox app (that one installs through the Apps tab in the My Cloud Dashboard) is not supported on the second generation single bay My Cloud.
For second generation single bay My Cloud users they may have to try GoodSync to see if they can use it to backup to Dropbox or other online cloud storage sites.
Thank-you. I read the manual but it doesn’t mention Dropbox at all or anything about powered external USB. I don’t know what a BestBuy is - I’m in the UK.