How to create self signed certificates for Rancher 2.6?

Hi,I am trying to install Rancher as explained here:

but I can’t get ssl Certificates working. Does any1 have example commands for openSSL which I could use to create those 3 required parts:
|<FULL_CHAIN.pem>|The path to your full certificate chain.|
|<PRIVATE_KEY.pem>|The path to the private key for your certificate.|
|<CA_CERTS.pem>|The path to the certificate authority’s certificate.|