Import root.cer, server.pfx and client.pfx certificates

I have to install these three certificates (root.cer, server.pfx and client.pfx) genereted by Qlik Sense in a Ubuntu machine.

My cenario:

The above link describes what I have to do for Windows, but I need the same result in Ubuntu. These steps works for Windows.

There are two diferents way to import, one for .cer and another for .pfx.

In Ubuntu should I consider “Trusted Root Certification Authorities” and “Automatically select the certificate store based on the type of certificate” steps diferences?

My search found lots of commands and conversions, but Im really lost about it.

What steps should I do to install these certificates?