Some software is delivered automatically to your computer. Some software is offered à la carte. This allows you to choose software that might be helpful to you.
The first step is to look for the red Filewave pennant in the menu bar (top of the screen) of your computer:
Click on it, and a menu drops down:
If the computer is verifying software, that bottom won't be available to your computer. The installer is installing something else. Check back a little while later. When you can click on Install Software.... do so.
You are now given a menu of options:
In the above menu, you can see some items are installed. The uninstall button may be there, or the option is grayed out if that's not available to you. Other software has an install button awaiting to install.
I Installed it ... but where is it?
If you just pressed the install button, it needs time to install. Once it installs, you will find it in your applications folder. To locate this folder, look on your desktop for the icon labelled Macintosh HD. Click on Macintosh HD, then look for a folder called Applications.