i am new to centos i wanted to install latest version of x window system on centos 8 but i was unable to find anything useful
can you guide me in installing x window system on centos

Red Hat (Now the OWNER of CentOS and CentOS Stream: and what you have is CentOS Stream) recommends you use the version in the REPO.
Why install CentOS Stream 8 when CentOS Stream 9 is in release and has more recent software versions?

If you were to download and compile current sources from X.org you would avoid any of the CentOS Stream specific patches and fixes added by the RHEL team, and configuration to make it work better specific to CentOS Stream. You would also be stuck with that version, and no security or fix patches for it, until you download and compile a newer version. You are FAR better off using the most recent version in the CentOS Steam repositories. That will be more up to date if you use the most recent version of CentOS Stream.