Networking in general with Linux is a wide field. It is one of those parts where the operating system is strong and offers lots possibilities. I would suggest different steps:
Getting an IP address
At first every computer in your network needs an IP address. Most home networks have some kind of (DSL) router which offers DHCP. That means you'll get automatically an IP from your router and don't have to worry about.
Avahi is another easy form to connect your computers in your home network. You need
avahi-daemon installed. Furthermore the package
libnss-mdns is needed. If the avahi daemon runs, you can connect to other computers in your network with
computername.local. They will assign an IP and use their hostname for connections (If you forget the hostnames, open a terminal and type
Fixed IP address
If the above is not the case the next easy solution (in my opinion) is to give every computer a fixed IP address. For me the easiest way is to edit
iface eth0 inet static
Those lines assign the IP 192.168.0.42 to the network interface eth0 on that computer. Other information like netmask, default router etc. can also be entered into that file.
Another possibility is to install an DHCP server. This is usually more complex. I will not cover this here.
Getting a name
Under normal circumstances only connecting via IP addresses is not nice. You have to remember all those numbers. So it gets easier with names. If you only have a few computers in your network, you can edit
The first entry is the IP address and the second is the name you want to use. Now you can use
images to connect to the computer with IP 192.168.0.65. This file has to be on every computer in your network.
If you don't want to distribute that file across your computers, you can use a DNS server like BIND. But setting this up is too complex for my answer. ;)
Now every computer has an IP address and a name. You can connect to them.
Nautilus allows you to share files. Just click right on a folder and choose it too be shared. Eventually Ubuntu will install some missing files. Choose a name and access rights for that share and you're done. If you use the
ahavi-discover it is easy to access the files.
A special application is giver. Every computer needs to run this software. With drag&drop you can share files between computers. Besides this you can also use Pidgin, an FTP server or Samba to access files.
Here we need Avahi again. Install
python-avahi and choose Pidgin as chat software (also Gajim is able to chat via Bonjour). Make a new account and choose Bonjour as communication protocol. If you start Pidgin and other Bonjour-users are active in your network, you'll see them and can chat.
As said before there are several other possibilities to chat. I chose only this. Furthermore you can configure those services in specific ways. If you have questions it would be the best to ask them in more detail. Have fun with your network. :-)