$ sudo apt update $ sudo apt install ca-certificates $ sudo curl -o /usr/local/share/ca-certificates/orwtmc-ecc-root-1.crt https://pki.frank-ruan.com/frandustry-root.crt $ sudo update-ca-certificates
Download the .crt certificate and double-click it. The operating system will guide you through installation.
On Windows, make sure to install the certificate to Trusted Root Certification Authorities (usually the second option from the top).