Child theme: How to access the cpanel?

Hi,
I am a very beginner on WordPress and I am creating my first website. I red a lot about the child theme and I understand its purpose. However in order to create it, I have to access my cpanel (which Ihave no idea what this is). I am register with Dreamhost and I can’t find my cpanel with my dream host account.

Again, I am a beginner and don’t really understand the css and coding language.

Thank you for helping me in a clear and easy language.