For a new Red Hat-based install I’ll assume you also need a new DB2 database installation… If that’s the case, you can download DB2, our BigFix limited-use license for DB2, and the BigFix installers through the License Key Center. Links & instructions for the Key Center are at https://support.hcltechsw.com/csm?id=kb_article&sysparm_article=KB0093384
There is no “standard path” for the certificate private key (pvk file). Best-practice is for the file to not be on the server at all, but stored on external media or in a privileged access system like Cyber-Ark or LastPass or Vault or similar. That said, many customers do store it on their root server but you may need to search for it.
When you run the server installer script, it will prompt for whether to use an existing key, and then will ask you for the paths to the masthead, certificate, and pvk files. It will also ask for the paths where you downloaded & extracted the DB2 installer, and will install & configure the DB2 database for you.
The masthead lists the root server URL, so in order to move clients you’d want to setup a DNS alias to direct the original masthead name to the new root server.
This is an area where your TA or Services can help, so let us know if you need some assistance.