If you're using a Shopify free theme, while on a paid plan, then this would be a request we can escalate to our Themes team. You can create the request by contacting Shopify after logging into your store through the help center, searching your question/issue, then selecting "continue" at the bottom of the page that displays the search results.
If these are instructions, then it may be easier to offer the instructions via a PDF file that customers can download. You can upload the file to Settings/Files, then hyperlink the URL to your product page.
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