Alternative #1: Use the webpage https://www.messenger.com/. Alternative #2: Download the unofficial Messenger for desktop app, https://messengerfordesktop.com/. This is actually the webpage in a shell. This is based on a open source project. But the page tries to push some other apps on you now, so I’m running away from this app 🙁 My recommendation, Alternative #3: Use the Windows app by Facebook, https://www.microsoft.com/en-us/store/p/messenger/9wzdncrf0083.