How to upload videos and play in Drupal 7?
Here is complete Community Documentation about the Media module.

There is another Drupal Video Setup Using Media and Media Youtube
 tutorial about using the [Media] and Media Youtube modules in a Drupal site.

If still you can't get it to work, then you can also check the tutorial Post YouTube Videos with Media + Media: YouTube (from Drupal's Post Installation forum).

Now choice is up to you in which you feel easy.