Unless you've changed the default settings, the place to start in XP is [Start -> Programs -> Accessories -> Command Prompt,] and type the commmand:
If that works, you're off to a good start.
See page 64, the section about Share Folders. These are not visible by default. Then look at the picture in the middle of page 65. Select a folder name (or name one that you create yourself,) tick the buttons for Browseable and (possilby) Public (though you may choose to change this later if you connect to the internet.) Apply your changes with the button at the bottom of the screen (might have to scroll to see it.)
My network is CIFS/Samba, and yours might not be, so I can't say much more without some feedback from you on the forum. I avoid giving advice about topics for which I'm not on solid footing. Please let me know if you question anything I've said.
I don't think the manual was originally written in English, but it's better than most, and the sequence of the chapters is logical.