The Installer will only ask for a Platform Edition if it is a fresh install. If Ignition is already installed, the installer will detect that, and upgrade instead. If you wish to install Edge on a computer that already has Ignition, you will need to first uninstall Ignition, and then run the installer and select Edge.
Once you have selected an Edge installation, there is no option for a custom installation that allows you to select modules. When installing Edge, the appropriate modules will be added for you.
Once the installation process is done and the Edge Gateway has finished starting, navigating to localhost:8088 in a web browser will take you to the Ignition Edge Gateway Webpage. You will notice the Gateway will be green instead of our usual orange color, so you instantly know this is an Edge install instead of a full install.
Once Edge is installed, you can start using it. It has the same two hour trial as the full install of Ignition.