Turn on the ‘Talk’ feature in the app interface under "Sounds".
Note: The app may request access to your device’s microphone. Make sure to allow microphone access when push-to-talk prompts (through pop-up or address bar) in your browser.

Once connected, the ‘Push to talk’ button will change to blue and be active.

Click and hold the 'Push to talk' button.

When you see “Talk now”, you can speak through your device’s microphone and respond to any question during the interview.

When you are not speaking, simply release the "Talk Now" button. Then repeat the above-explained steps when you wish to speak through ALEX.
Note: Push-to-talk speech is not added to the logs.