Access to shared files and directory

I run at home a workgroup network with XP Pro, EI 6 and Netgear Router MR814
V2.
I use a broadband dialup ISP with user and password access.
I managed to give access to Internet to all workstations.
However, I did not manage to give them access to shared files and
directories.
I run "Set up a home or small office network" and uploaded the related
diskette, which was passed to all stations.
Useless.
Anybody can give me a hint where it was my mistake and furnish me with a
good guidance ?
Appreciate assistance.