Up to two icons are used for each package to show you its status and selection.

On the left, you can see if the package is already installed:

The package is already installed. Single-click on the package to have the installed version displayed at the bottom of the page.
The package is already installed, but the version of the package in the current archive is older than the installed version. Reinstalling this package will downgrade your installation, which is probably not desirable.

If you see only one icon, the package is not yet installed. The icon on the right shows you whether the package is currently selected for installation or de-installation (removal):
The package is not currently selected. WarpIN will not do anything about this package: if it is already installed, it will be left alone. If it is not already installed, it won't be installed either.
The package is selected for installation. If the package is already installed, the existing installation is replaced.
The package is already installed and selected for de-installation (removal).

To change the selection for a package, double-click on it.