Video does show up in preview

hi , i am trying to have a video trailer play in the beginning of a game and after trying the script , it said first missing audio source the child object and it gave me a white screen that does not play any movie , does anyone know why is this happening . i read some articles and they are saying after the movie texture is imported it is supposed to have an audio source imported with it as a child but it did not

you should attach the audio of movie texture separately. and you should paly the movie manually in a script.

Thanks for your answer , let me explain again as maybe i was not clear enough.

The Video that i imported does not have a child audio imported , according to what you are saying i should use one of video editing programs and extract the audio signal too. Is that what you meant. the Script does not play the movie as the movie preview is just that white screen that does nothing. however if i click on the video in the inspector it shows the video that it is imported successfully but also with the white screen preview under the preview option.

How to do it