To start installing and using software from a Personal Package Archive, you first need to tell Ubuntu where to find the PPA and how to verify the authenticity of its software.
Step 1: Copy the first line from the apt sources.list entries section of the PPA overview page.For example:
deb http://ppa.launchpad.net/awn-testing/ubuntu jaunty main
Step 2: Edit the sources.list. Add source to your sources.list
sudo gedit /etc/apt/sources.list
Step 3: Authenticate the PPA. Find the PPA’s OpenPGP key id the overview page. It looks something like this: 1024/12345678, copy it.
sudo apt-key adv –keyserver keyserver.ubuntu.com –recv-keys 12345678
Replace 12345678 with the key id
Step 4: Finally, tell Ubuntu to re-load the sources.
sudo apt-get update
You’re now ready to install software from the PPA!