If you’re using samba to share your files in network,there’s a recommended GUI tool system-config-samba that you can easily create,delete and configure shares with a graphical interface.
First,make sure you have installed samba server in your ubuntu.
And now,you can install system-config-samba from System->Administration->Synaptic Package Manager.Search “system-config-samba” in search box,choose to mark and click Apply to install.
After installed this tool,you can launch it from System->Administration->Samba.
samba

To create new share,click on Add Share,and in this screen type details.

samba1

To get access to the share folder from Windows PCs in the network,go to Start->Run and type \\hostname\share_name.(or \\IP address\share_name),you can use this command in terminal to get your ubuntu hostname:

hostname

Or,just type \\hostname after Start->Run and you will get all shares from this PC.
Tips:
if you want to share files between Ubuntu PCs,using sshfs maybe more easily and friendly,just like mount windows drives on your desktop.
Networking ubuntu PCs with sshfs