Quoted from the tips page: "Imperative E
E is used before an action to signify a command or a suggestion. When you say, "E hele", you're telling someone to "Go!"
E is used before a noun (usually a person) to indicate that the person is being addressed.
Ex. Mahalo, e Kawika. ➜ You are saying thanks to Kawika."
You can't get these notes on the app, but they're on the online course.
They have lesson notes if you click on the lightbulb symbol on the lesson. It says that e is used 1) as an indicator that you're talking to someone and 2) to indicate that something is a command (imperative). It has no direct translation in English, I'm afraid, it's just a structural thing in Hawaiian.