If you’re trying to have two gateways installed on the same machine, you’ll need to make sure they have different service names, otherwise you’ll see issues installing the service. In ignition.conf, there’s a property near the end of the file called wrapper.name - for the Edge install, you’ll want to change that to something other than Ignition so it doesn’t clash with the service name for the Ignition install. After making that change, you can properly install the service.
If you want the gateways to run at the same time, you’ll need to modify data/gateway.xml in the Edge install directory to use different ports than the Ignition install.