Installing softwares in ubuntu is very easy1. Open the software center and find the software from a stack of software's and hit the install
button. Your software is installed.
2. If you wann do it in hard way open a terminal and write the following command(cmd) in terminal
sudo apt-get install chrome (for ubuntu)
yum install chrome (for rhce and fedora)
3. You can also install software from synaptic package manager in Ubuntu.
4. you can install software from http://www.getdeb.net/ for debian based linux
In all of the above method you need a working internet connection.
There is also other way to install software
You can download software from internet if it is a .deb (for debian based) or .rpm(for reh hat based) package then you can install them by double clicking on them.
If this is a zip file or tar file then extract them and their is a file in it readme read that file follow the instructions. ther are simple three steps
3. make install
and your software is installed.