There are two ways to upload your content on youtube. One is normal through which you don't earn anything and the other way is to monetize it and earn money.
If you are expecting to earn via youtube then remember to include only original content in your video. There are several royalty free content available to include in your video like audio or images.
And even if you post any video for which someone else has the copyright, then it is upto the copyright holder to either allow it on your channel or block it. In many instances, copyright owners allow it but the revenue generated via ads on the video on your channel is also sent to the copyright owners.
Means you can keep that video on your channel but you will not earn anything.