When you install the Telmediq app, as long as your Apple Watch is paired with your iPhone, and you have not disabled Automatic App Install, the Telmediq Watch App will immediately be available.
If you haven't paired your Apple Watch to your iPhone instructions can be found here.
Notifications for Telmediq messages will be available on your Apple Watch. You will be required to enter your 4 digit PIN before interacting with the message.
When you have read the message, you can record an audio note reply from the Apple Watch.
Note: The alert tone used for notifications is the default alert tone for the Apple Watch, it will not alert with your Telmediq alert tones. You cannot change the alert sounds on the Apple Watch as of today, but you can change the sound volume.
Note: If you silence notifications, or turn on do not disturb on your Apple Watch you will not receive any audio alerts for messages from Telmediq. You can adjust these settings, and the volume of your alert tones by following the instructions posted by Apple here.
If you want to adjust your notification mirroring settings, follow the instructions here. Where you will be able to toggle on and off receiving Telmediq notifications on your Apple Watch from the Apple Watch Notifications menu: