Ringtone Phone change

How do I change the ringtone on contacts; I mean change them all [same type]at the same time, not one by one

thanks for the help

Also for an extra tip on my iphone I had a voice memo that I used as a ringtone and wanted to keep it.
So in itunes I copied it as an mp3 then uou can create custom folders which the vibrant will recognize for custom sounds. Create a folder called "Media". In that, create a folder called "Audio". In the Audio folder create folders called "Ringtones", "Notifications", "Alarms". If you put custom sounds in those folders, you will be able to select them in your settings.

I found that tip while googling various things.