Download the app from https://kezayo.com/download. The apps are not yet signed with an Apple or Microsoft publisher certificate, so your computer asks you to confirm the first time.
Mac 1. Open the downloaded .dmg and drag KEZAYO into Applications. (Apple menu → About This Mac tells you whether you have Apple Silicon or Intel.) 2. Open KEZAYO from Applications. If macOS says it can't verify the developer, click Done. 3. Go to System Settings → Privacy & Security, scroll down and click Open Anyway next to KEZAYO. 4. Allow camera and microphone, and Screen Recording if you want to share your screen.
Windows 1. Run the downloaded .exe installer. 2. If "Windows protected your PC" appears, click More info → Run anyway. 3. Follow the installer — it adds a desktop and Start-menu shortcut. 4. Allow camera and microphone when Windows asks.
Linux 1. Download the .AppImage (or the .tar.gz archive) from the download page. 2. Make the AppImage executable: right-click → Properties → Allow executing as a program, or run chmod +x KEZAYO-*.AppImage. 3. Double-click it to start KEZAYO. If it does not open, install libfuse2, or run it with --appimage-extract-and-run. 4. Allow camera and microphone when asked.
The desktop app shows the same meeting screen as the browser.