The Kayak splash screen describes what the app is for and gives us the option to connect with Facebook/Google, or sign in with email.
The Facebook & Google buttons are more visible than the email sign in one.
There's also a "x" in the top-left corner that lets us continue without signing in/up.
We go ahead and sign up using out email.
We're now in the app. The page we land on is the hotel search page. It's pretty self-explanatory, so most people should be fine exploring the app from here.
We get the standard iOS notification permissions alert when we land here.