Apps (applications) and plugins (extensions to applications) are the dedicated software tools that can perform specific tasks within your system. Sometimes these terms are used interchangeably in the home control world, because there are so many different products and manufacturers. But for your purposes, they're conceptually the same thing. Much like you'd download an app to your smartphone to give it a specific function, you're doing the same thing for your Vera 3 system.
On the Dashboard, click Apps, then the submenu to Install Apps. You'll now see a broad selection of available apps and plugins available to you (with more coming all the time).
When you see a plugin you'd like to install, all you need to do is click the Install button that accompanies that device's description. In a moment the app will download to your system and you'll be ready to work with it through your Dashboard.
To see the apps and plugins that are active in your system, click on the submenu item My Apps:
You'll be presented with a list of your current apps. Click on any of them to inspect their specific properties, change specific settings or see reviews on this app from other users.
Some apps and plugins are necessary for the actual functioning of some specific devices. Other apps and plugins are completely optional to your system. If you download and app and then decide you don't need or want it in your system, you can remove it from your system by clicking Uninstall for that particular app or plugin.
Now that you've added functionalities to your system, let's see how you can adjust them to your preferences and commands.