The github link in the first post has very detailed instructions. https://github.com/drsprite/OpenSprinkler-Push-Notifications
Further, OpenSprinkler has something built in, too. https://openthings.freshdesk.com/support/solutions/articles/5000716372-creating-an-ifttt-key-and-applet
I can’t speak to the level of detail that the built in function has compared to the script we’ve been running for the last couple of years.