A little background here ...
If you're not finding the systems that you expect to see, you need to consider the answer to three
- How do the systems in question share their files? Do they use the Windows protocol (e.g. SAMBA), or the Unix Network File System (NFS) protocol, or something else?
- (Never overlook the obvious ...) Do they in fact share their files? Are they on-line? Do you in fact have network connectivity to them?
- What file-sharing protocols does your system support, and are the necessary system-services etc. that may be needed to provide that support actually running?
In my experience, problems like these often turn out to be "great big time-wasters" because the solution usually turns out to be "quite simple, even painfully obvious," when I
stopped 'assuming' and actually 'checked.'
Unlike Windows, which rather blissfully assumes that "nothing in the Universe exists except The Microsoft Way™," Linux is built to support the real world ... with many options at your disposal and therefore more parameters which all must be configured in just the right way. A very systematic trouble-shooting process is needed... "check everything, assume nothing."