Steps to configure VNC server on CentOS:

//First verify version & redhat-release by following command:
[root@centos ~]# cat /proc/version
[root@centos ~]# cat /etc/redhat-release

//Install required packages:

[root@centos ~]# yum -y install tigervnc-server xorg*
[root@centos ~]# yum groupinstall "General Purpose Desktop" –y
OR
You can download repected rpm of "tigervnc-server, xorg & General Purpose Desktop" from web.

[root@centos ~]# vncpasswd
Password: supp0rt
Verify: supp0rt

//Edit this file as below
[root@centos ~]# nano /etc/sysconfig/vncservers
VNCSERVERS="2:root"
VNCSERVERARGS[2]="-geometry 1024×800"

//Restart VNC-Server services by issuing following command:
[root@centos ~]# service vncserver stop
[root@centos ~]# service vncserver start
OR
[root@centos ~]# service vncserver restart

//Edit this file as below
[root@centos ~]# nano .vnc/xstartup
#twm & //comment last line.
exec gnome-session & //add this line

//Stop all iptables.
[root@centos ~]# /etc/init.d/iptables stop

//Restart VNC-Server services by issuing following command:
[root@centos ~]# service vncserver stop
[root@centos ~]# service vncserver start
OR
[root@centos ~]# service vncserver restart

//Access vnc from browser:
URL: <IP_address>:5802
OR
You can use VNC Viewer to take access.

You will get GUI of the same server.

***********************************************************************
Note: Please don’t hesitate to revert in case of any query OR feedback.

Thanking you.
Have a easy life ahead.