That connect string is Windows feature. On a Mac:
In Finder open Go > Connect to Server... (or press Cmd+K)
then type into that box either
smb://yourNASname.local/ or smb://your.nas.ip.addr/
or, better yet, if you enabled AFP server under DNS-320's Application Management, you can use
afp://yourNASname.local/ (or IP if you prefer)
in your connect string.