Installing a child theme over a parent theme

Hi, I want to make a few visual customisations to my site so I’ve been told I need to edit the child theme of my site. Trouble is I haven’t installed a child version of the Studio theme I’m using and have never used Child themes before.

I’ve read and have a conceptual understanding of how they work. But does this mean if I’m currently using the parent theme, I won’t be able to now use the child theme and continue to use the site as normal?

Tips and advice would be much appreciated.