I have a C8 so it should be about the same.
Power off the router
Connect the drive to the router.
power on the router
Enter http://192.168.0.1 (some cases you use http://tplinklogin.net/ in your browser and press enter
Sign on to the router.
Go to the "advanced: tab
Select the "USB Settings"
Be sure the printer server option is disabled
In device settings you may need to select scan.
In file sharing, select the options you want. I selected /'use login account", enable "network neighborhood", and "share all"

Note that the router does not support the Apple formats. The drive can be formatted like a windows drive (NTSF or FAT32) and an Apple computer can read/write. However Time Machine will not work on the Router drive.

To use the USB hard drive attached to router
Windows 10

[*]Press the Windows Key and R
[*]Enter \\192.168.0.1

[*]Apple OS
Open a Browser (Chrome, Safari, …)
[*]Enter SMB://192.168.0.1
[*]Select to open in finder