I believe your theme is filtering the richtext with escape. I do agree with the suggestion to do this using metafield. Since every product has different ingredients. You can follow the instructions below on how to use metafield for this.
From your Admin Page, click Settings in your left hand bottom corner
You should be able to enter the information in your product. Go to your product, and assign each paragraph as a line of item. Add items as many as you want. Please see image below. Make sure to click SAVE
In which part of the liquid under Edit Codes, should I add these codes. I am not able to follow the Theme editor explanation. Can you kindly provide it detail?
I am trying to add a details in product description as shown below.
Depending on your theme. If you have an option to have custom block under the product template, I would suggest using it. Otherwise, you might need to hire someone to read and add the code for you