You can stream the audio to your AirPlay compatible speaker using the Control Center on your iOS device by completing the following steps:

1. On your iPhone or iPad, open Control Center by swiping down from the top right of the screen.

2.  Find the audio icon in the upper right-hand corner and then tap the AirPlay icon.

3. Select the speaker from the list of devices to stream audio using AirPlay.
 

You can also use AirPlay directly from some iOS apps, like Apple Music by:
1. Opening the app.
2. Tap the AirPlay icon.
3. Select your AirPlay compatible speaker.