Looking to access your theme's code or language options with Shopify's new theme editor layout?
In your Shopify admin click on Online store > Themes
Next to the theme that you want to edit click on the Menu button which is a small square with 3 blue dots
This will open a submenu of options which includes: Edit HTMl / CSS and Edit Language
To add content to this go to Themes > Customize theme > Product page in your Shopify admin.
Check the box labelled: Show content accordion
Beneath this you will see 3 dropdown options which allow you to choose content from pages within your store. Choose the relevant pages and click save.
Should you update those pages in the future this will now auto update.