How do people have clips from TV programs on youtube?

Are you talking about movie music videos? In that case they would either find a clip of the series online, like a fan site of TV series site. There are programs you can download that allows you to download these clips from the internet if there is no download option for the clip. And how those people get the clips that support movie music video or TV music videos, either they get permission from the company to use the clip or find a way to digitally record the clip and transfer it into a video file that is readable for online players. Like .flv .wmv and so on and so forth. Look up tutorials online if you want to use movie maker. Even though I hate movie maker. Sony Vegas all the way.