After download, extract cart_v3.zip to where you keep your Alpha Five projects. For example, if you keep your Alpha Five projects at c:\a5projects, then you would have this structure after extracting the files:
c:\a5projects\cart_v3: a folder containing the Alpha Five web project.
c:\a5projects\cart_v3\extras\cart_v3_MYSQL.sql: the dump file used to create your database if you are using MySQL.
c:\a5projects\cart_v3\extras\cart_v3_MSSQL.sql: the dump file used to create your database if you are using Microsoft SQL Server.
c:\a5projects\cart_v3\extras\downloads: folder with sample "download files". This gets copied to your "data" location, discussed later in this document.
c:\a5projects\cart_v3\extras\docs: any documentation.
(There may be other files in the "extras" folder not listed here.)
Drag the "extras" folder out of the project, perhaps to your desktop. This folder contains help documentation and other resources that are not part of your Alpha Five project.
Before you go any farther, make a copy of your cart_v3 project, keeping your original copy as the "master". This will allow you to apply updates from AlphaToGo to the original installation.
The best way to make a copy of an existing project is to use the batch file named copy_a5_project.bat, included in the "extras" folder.