Navigate to your Downloads folder, select the appliance and then click Open: In the GNS3 user interface, click File and then Import appliance: Please refer to other guides for more details on how to install the GNS3 all-in-one package and how to download and configure the GNS3 VM.
This document assumes that you already have both the GNS3 Graphical User Interface installed (GNS3-all-in-one) and the GNS3 VM integrated with GNS3.