You can download the desktop app for Windows, MacOS and Linux here: https://twake.app/fr/download
The mobile app is available on iOS App Store and Android Play Store.
On the desktop app, you can use the following options to change your server:
• On MacOS, click on Help > Change Twake Server • On Windows, MacOS and Linux, use the shortcut CTRL+ALT+SHIFT+S or CMD+ALT+SHIFT+S
On the mobile app, just log out and you should be able to change the server from the bottom left login page link "Change Server".
This feature is not yet available, say you want this feature using a "thumbs up" emoji here: https://github.com/TwakeApp/Twake/issues/130