This is premium only feature, you would need to be on at least "Professional" plan.
Note: If you would like to add FAQs to only specific products, please follow this tutorial.
In this example, we will create new FAQ page with only two categories.
1. Visit your store's admin panel.
2. Click on "Online Store" > "Pages" and then click on page where you would like to show FAQs.
3. Let's call it "Returns and refund" and then put contents of your choice.
4. Open FAQs app and head over to "Categories", click on "Copy code" for "Return and refund" category.
5. Come back to your Shopify admin panel where you are creating a new page and paste code you copied in HTML text area.
If you wish, you can copy codes from more than one category and have it display on a single page.
6. Save page and open this page on new tab, you should see FAQs from "Returns and refunds" category on this newly created page.
7. If you still don't see FAQs on your page, make sure you have enabled a feature through settings. Please follow these steps to make sure feature is activated.
Design and Settings > General > Show FAQs on other pages > View Settings > Activation > Activate.
After activation, you should start seeing FAQs at appropriate place.