OK
So I had a little look through the documentation and it's pretty useless in terms of being user friendly. So, for the benefit of others who get stuck at this hurdle here's what I discovered by trial and error.
It turns out that once the DNS is set up on your network it appears within my own PC's directory tree as a DLink DVD RW drive. From here I discovered a folder called DOC with various PDFs one of which refers to client software called the ShareCenter Sync Manual.
I installed the exe file for the ShareCenter Sync software from this DVD drive onto the PC (Windows 7) and set about creating a backup task.
All very straightforward... when you know where to look.
Frankly I think the software on both the NAS via a web browser and for the client PC are pretty poor by comparison with the efforts from Synology... but I'm prepared to persevere!
A quick aside, the browser interface does not seem to play nice with Firefox.
Ralph