Installing Webmin on CentOS or Redhat is extremely easy using yum. Yum also allows you to keep Webmin update to date extremely easy (yum update)

• Enter "nano /etc/yum.repos.d/webmin.repo"
• Paste the following text

[Webmin]

name=Webmin Distribution Neutral

#baseurl=http://download.webmin.com/download/yum

mirrorlist=http://download.webmin.com/download/yum/mirrorlist

enabled=1

• CTRL+O to save then CTRL+X to exit.
• Install the GPG key.
  • "wget http://www.webmin.com/jcameron-key.asc"
  • "rpm --import jcameron-key.asc"

• Enter "yum install webmin"
• Once Webmin has finished installing you should be load the following address in your browser. http://youripaddress:10000

references: https://www.hooplahosting.com/client/knowledgebase/87/Install-Webmin-on-CentOS-or-Redhat-using-yum.html