OK, I figured out how to setup samba shares - you have to know:
- share IP. I gave static IPs to my NAS'
- Remote Directory name - basically, your shared folder on Windows machine or share name on NAS.
- Username/Password - for my NAS (some kind of debian) I was able to set up a linux user and use its username/password as credentials here. For XP shares any enabled user account for the XP box will work. I have a user with no password and it works fine.

The only thing I cannot resolve is those Shared Folders that should appear in a File Manager by default. Curiously enough, I have them appeared in my office with network domains and elevated security, but not for my WORKGROUP at home.