If you ever try to connect My Flow from your Opera for Desktop with your Opera for Android, you may find out that "these devices never finish connecting" because Opera for Android give you a confirmation code that never shows up on your Desktop version. If this is your case, here is how to solve it:
On your Opera for Desktop, instead of open My Flow to scan the QR code, open this link
https://auth.opera.com/account/v3/desktop/login/scan-code. This link will give you a QR code to scan.
On your Opera from Android, Opera My Flow and scan the preview QR code. After that, it will show you the confirmation code on this Desktop. Confirm it and done. Now you will have Opera Flow connected with your Android.
Note: If you are using Opera Touch on Android, this problem does not apply to you. Only for User that have Opera for Android installed.