When you download a program, you’re actually downloading an installation “wizard” that installs the software for you. Go to your Downloads folder and double-click the file for the software you just downloaded. The window that opens is the installation wizard. It’ll guide you through some prompts, such as asking where you want to install the program and if you’d like to create a desktop shortcut. When you have made it through all the steps in the wizard and it closes, you can open your application and enter your activation key.