Open the Downloads window
Open your web browser's Downloads window and double-click on the Wuala entry.
Install Wuala by dragging the Wuala icon to the Applications folder.
Recommended: Install OSXFUSE
Double-click on the OSXFUSE icon and follow the setup wizard.
With OSXFUSE, Wuala is perfectly integrated into your system. This allows you to edit and stream files directly. You can also access the Wuala Drive directly in the Finder.