Your question:
"How do I play a .rar file on Windows Media player, I have WinRAR programe."
still doesn't make sense, assuming that by WinRAR you mean the same thing that I've got on my machine.
If you have a file whose name ends in .rar it may or may not be an archive file that WinRAR understands. If it is, then you can use WinRAR to extract the contents, which will be further files and/or directories. Some of these files might be video files, just as they might be anything else - we won't know unless you tell us. To find out, double click on the .rar file and see what WinRAR tells you about it.
On the other hand, it is possible that you have a video file in some video format or other that also uses the extension .rar. There is, regrettably, no law of nature that stops two different organisations choosing the same extension for two completely different and unconnected purposes. If this is the case then (1) WinRAR won't understand the file, and (2) you'll have to find something that does understand the particular format of file that you've got.
Whatever,
there is no way that WinRAR is going to play video. That just isn't what it does. Assuming that by "WinRAR" you mean
this thing and not some different completely unconnected thing that might also be called "WinRAR". (Just like file extensions, there's nothing to stop two organisations using the same name for their software, unless one of them can actually be bothered to sue the other and even then they might lose.)