Upload files not sync them

macOS Mojave 10.14.6

I have 2 MyCloud drives…“the white one and the back one” The black one is the EX4 which is stored remotely, the white one is connected to my internal network.

I wish to upload files to the EX4 via the app. Not to sync. I have sync set up on both machines but clearly if I delete a file it goes from the EX4.

I can drag the files to the window; but I got the message you can do it this way but lots of files do use WDsync (or something similar)

My question:

How do I upload files using WD Access to the EX4. (I can connect to the “white one” which is on my network)

How do I link to the EX4 using the app?