There're two Bluetooth scenarios you need to connect through the Spark Amp , one is to pair it with your iOS devices, the other is to connect it with the Spark Amp app. 

To pair Spark Amp with your iOS device:

1. On your iPhone/iPAD, go to Settings > Privacy> Bluetooth and enable Spark Amp app.

2.Go to Settings>Bluetooth and enable Bluetooth, stay on this screen until you see Spark 40 Audio is detected under My Devices.

3. Tap Spark 40 Audio to pair.

To pair Spark Amp with Spark Amp app on your iOS device:

1. Download Spark Amp App at: https://apps.apple.com/us/app/spark-amp/id1457653921
2. Launch the app and connect it with Spark Amp.

3. Click on the top left setting icon to enter the menu, you can check firmware version and serial number under Hardware Settings.

* If you miss the connecting notification while launching the Spark Amp app, you can always connect your Spark Amp under the setting menu in the app.