In this example, the 'Home screen' is customized and might look a bit different. The icon is red framed with a triangle inside of a white square that looks like a TV screen. Tap it once to open the application.
Tap on the three horizontal lines icon in the top-left corner of the screen
Opening the application should have automatically taken us to the 'What to watch' page which will be either specifically recommended videos we've watched (if we're signed in), or if we're not signed in, it will be the most watched or most popular videos on YouTube at that time. We can refer to the article on how to sign in with 'YouTube' on the iPhone 6 if we don't know how to sign in.