Windows Explorer > Network can be viewed by clicking Network
on the left side navigation pane:
Highlighted part of Explorer screenshot above shows computers belonging to same subnet.
Command ipconfig /all
in Command Prompt also shows computers and devices in your network.
If your device is not shown in these, it will not belong to same subnet or as UsernameIssues has told previously in this thread it is hidden from network. In this case you need to change network settings on your device (Blackberry).
I have absolutely no knowledge of Blackberries so I can not help you in that.