To modify your child theme you first need to enable Development Mode in the backend of your WordPress site.
Go to: Appearance -> Settings -> and click the checkbox to enable development mode.
Now go to the frontend of your site and right click somewhere on the page. Select Inspect (Eleement) and look at the HTML and CSS.
Example. Below one can see the site, then the HTML and on the right the CSS. In the HTML area beside tm-site is a data-markup-id”beans_site” this is important to know about for future modifications in the child theme.