First thing first.
Generate CSR from below link
Save the key and Private key securely.
A Certificate Signing Request (CSR) is a formatted message that an applicant for a Secure Sockets Layer (SSL) digital certificate sends to a certificate authority (CA). The CSR contains information that the CA uses to create the certificate, including the organization, country, and common name.
Get a free certificate
https://www.hostingwalay.pk/ssl-certificates.php
Certificate (CRT) will copied to CRT
PRIVATE KEY WILL go Pem keys