How do I make Calendar launch an app at a specific time?

All I want to do is have Calendar launch an app at a specific time. I can't you how many online tips and tutorials I've gone through. They all give the same basic steps but they do not exactly match the current version of Calendar. Bottom line, I can not get Calendar to launch an app on a schedule. All Calendar does is present a notification at the designated time.

The OS and Calendar should both be current: OS Sierra 10.12.3; Calendar 9.0. Here's what I do:

▪ Open Calendar

▪ Double click today's date to create a new event

▪ Name the event

▪ Click on the date to expand it

▪ Double click on start time and set it (for testing I generally set it a couple minutes into the future)

▪ Click Repeat and set: Every day

▪ Click Alert and set: Custom…

▪ Change Message to Open file

▪ A roll down appears with a default of Calendar. Change it to: Other…

▪ Select the app I want to open using the dialog

▪ Change the default time of "15 minutes before" to "at time of event"

Rather than launch the app at the designated time, a notification appears on the computer and all iCloud devices. When I open the repeating event for any future day they have all lost all the info that was set and alert has reverted back to: None

I've even tried creating an Automator workflow that launches the desired app. It works exactly as expected. When I set Calendar to run the workflow it still behaves exactly as above. Nothing happens except a notification pops up and all future events lose the custom alert settings.

I've tried this so many times I probably can't see the forest for the trees. What I'm I missing? Why won't this work?