Once you have installed the trial you will have to activate it. Here is the step by step on activating the trial. Once you install the software double click on the Powerpoint logo on your desktop. This will automatically launch the activation wizard. Now follow these steps:
1. Put in the trial product key and click, “continue”.
2. Click on the check box next to “I accept the terms of the license agreement” and click continue.
3. Now you will have activation option. Choose “I want to activate the software over the internet” and click next.
From here the wizard will take over. Just fill in any requested information and keep clicking next.

(The product key screen)