I just installed a fresh copy of Ubuntu 11.10. How to open the Synaptic Package Manager?
You need to install Synaptic first. You can do that by clicking here: Synaptic
or by typing
sudo apt-get install synaptic
in a terminal. (In order to open the terminal press: CTRL + ALT + T)
After this you just need to hit the Super key (or Windows) and type Synaptic and hit enter (to actually open the package manager).