To open a file with Stuffit Expander, first double-click the Stuffit Expander icon. Choose the Expand command from the File menu; then select the file that you downloaded. Click the Expand button. A dialog box will appear as the file is expanded into the same folder as the original encoded file (or onto the Macintosh desktop, if you didn't alter the default setting).
Find the folder the file was downloaded into. Double-click on the installer file that you downloaded. Click Continue at the product name. You will be taken to the installation screen.
At the installation screen, choose the location where you'd like to install your new software. If you install your new software into the folder that contains your current version of the product, your old version will be overwritten. If you wish to keep a copy of the old version as a backup, simply create a new folder for the software you are about to install.
When you see the prompt telling you that installation is complete, you will need to restart
your computer.