Here we'll guide you to manually trigger the siren via Reolink App following the steps below.
Step 1. Launch Reolink App and connect to your camera.
Step 2. Go to the Live View page and you will see the screen like the picture below.
Step 3. Click on the small bell icon on the top right corner.
Step 4. A prompt “Trigger sound alarms” will pop up. Click the bell in the middle to trigger the siren.