You just install the app via the Shopify app store, approve the charges and then click on install schema. Afterward, you just enable the snippets you need.
Rich snippets will help you to get more traffic to your page. It will help you to stand out from competitors since you have more data in your search listings than others.
The FAQ Schema is excellent because it allows you to take up a lot of space in the search listings. At the same time, you will already answer the most common questions of your customers before they even visit your store. To enable it, check out, which page category you want to enable it and add your questions and answers.