To install gnome 3 on ubuntu 12.04
1.Open Terminal.To open terminal click the Dash home from unity launcher.And type terminal in the search field. And click Terminal.
2.Type the below code in terminal and hit enter.
sudo add-apt-repository ppa:gnome3-team/gnome3
3.Type your ubuntu password if needed.
4.Then press enter to continue or ctrl-c to cancel adding the ppa.
5.Type below command and hit enter
sudo apt-get update
6.Then type below command and press enter
sudo apt-get install gnome-shell
Type your ubuntu password if needed.
Type y and hit enter to confirm Gnome 3 installation.
After the successful installation, reboot your computer and when you are prompted with your login screen click on the little Ubuntu icon next to your login name and select Gnome.
