Short answer:

To install software manually you will most likely need to download a .deb file (it's sort of Ubuntu's .msi equivalent), and then either:

1. Double-click it and install it through the Ubuntu Software Center.

Or:

2. Use the command-line (I will explain both).

Long answer:

Download Google Chrome here and click:

In order to download the .deb installation file.

It will likely ask you if you want the 32-bit or 64-bit one, download whichever is appropriate for your install, and accept the license agreement.

GUI Installation:

When the download is complete, open your file manager (probably Nautilus) and navigate to the location where you downloaded the file to (probably the ~/Downloads folder).

Then double-click the file, this should open the Ubuntu Software Center, to install click the Install button and then enter your password as prompted (your Ubuntu Software Center may look slightly different to mine in terms of design as I am on the GNOME flavour of Ubuntu):

In the above screenshot I have put a red box around the Install button you need to press.

Terminal Installation:

Now for the command-line Terminal installation, first open a Terminal window (Ctrl + Alt + T), then use the cd command to navigate to the location you downloaded the file to. You will probably need to go to the ~/Downloads folder with:

cd ~/Downloads

And then you will need to run the following command to install Google Chrome where you need to replace [filename] with the name of the file you downloaded. (Either google-chrome-stable_current_amd64.deb(64-bit) orgoogle-chrome-stable_current_i386.deb` (32-bit) ):

sudo dpkg -i [filename]

You will then be prompted for your password (though you will notice that even though it does not look like you are typing anything, in fact you are and this is just a security feature), enter the password and press Enter and that should install Google Chrome.