Create the ssl_cert.pem text file. The certificates for the cert chain will all need to be in PEM format, and listed as follows: server cert, intermediate cert(s) and finally the root ca cert.
openssl or https://www.sslshopper.com/ssl-converter.html can be used to change certificate formats from crt/der binary to pem format.
Create the ssl_key.pem text file. This is the private key for the wildcard certificate.
SCP using SecureFX or WinSCP these certs to Opengear /etc/config/ directory. Connecting as the root user.
SSH into the Opengear as root and run the command below
dos2unix /etc/config/ssl_key.pem dos2unix /etc/config/ssl_cert.pem config -a
If the browser is still showing the old certs, try and reboot the Opengear device.