https://www.theverge.com/2018/2/6/16974586/homepod-apple-speaker-ios-how-to

The new HomePod speaker from Apple goes on sale Friday for $349. If you’re planning on buying the premium Siri-powered music speaker, the first task you’ll be faced with after unboxing is setting the thing up. It’s not difficult, but it involves one very important decision.

To kick things off, bring a compatible iOS device (running iOS 11.2.5 or later) in close proximity to the HomePod. A prompt with a 3D model of the HomePod should automatically appear on screen. (If you’ve seen the AirPods pairing screen, this looks just like that.)