You don’t say if you’re on macOS or Windows. I’ll assume the former since you usually only have one version of the Simulator at a time on Windows.
You can either set it in your user preferences:
Sublime Text > Preferences > Package Settings > Corona Editor > Settings - User
with something like:
“corona_sdk_simulator_path”: “/Applications/CoronaSDK-2970/Corona Simulator.app”,
or in the build.settings for a particular project with:
corona_sdk_simulator_path = “/Applications/CoronaSDK-2675/Corona Simulator.app”,
Note that Corona Editor locates the most recent Daily Build in your Applications folder to run projects so setting the Simulator path is hardly ever necessary (except for older projects that require an older Simulator for some reason).