Check IP address.

open a dos window, keyin: IPCONFIG
to see the IP address.

You need set the Ip in the same sub net.
example:

192.168.0.1
192.168.0.2
192.168.0.3
192.168.0.4
192.168.0.5
...

Make sure they are on the same Group.

and then try to ping each other.
example:

ping 192.168.0.5

If you can ping each other, you need share the folder.