Customizing a Page in your Site with HTML/ JS
From the page that you're customizing -- in the left-hand sidebar, find the "Advanced" Block
Click on the Block, and drag it to the right to drop it onto your page.
Hover over the Block, and click on "Content" to open the Editor window.
Click the "Data" dropdown menu.
Toggle on the option to enable the code snippet (green):
Add your HTML or JS code into the field:
You can also customize the visibility for any Block on your page -- here's how.
Saving Your Blocks
Remember that once you customize a block, you can save it to use again on another page
You can access your Saved Blocks at anytime right here: