Open server console and login as root user, or open SSH and login as an existing user with root privileges

Update your system packages and ensure curl is installed:
dnf update -y
dnf install curl -y

Download and run the official Webmin repository setup script:
curl -o setup-repos.sh https://raw.githubusercontent.com/webmin/webmin/master/setup-repos.sh
sh setup-repos.sh

Install Webmin using DNF:
dnf install webmin -y

Enable and start the Webmin service:
systemctl enable --now webmin

If you have a firewall enabled, open the Webmin port and reload rules:
firewall-cmd --permanent --add-port=10000/tcp
firewall-cmd --reload

If you have Premium OS support from us, we can configure the Firewall for you.