Anybody know how to play downloaded ringdoor bell videos on phone?

Hello, I've downloaded a video clip from my ring doorbell, and it will not open or allow people I have tried to share the clip, to open and watch it either.It either advises i don't have the app to play this video. I've then gone to playstore and downloaded the apps it suggested, and they still wont work. Its has downloaded as an MP4 file.Can anyone help or offer advice??