First, navigate to the page you want to designate as your FAQ template and change the template setting to page.faq.
The dropdown will only have the page.faq template option if your theme is currently published.
Second, open your theme editor and navigate to that page. This is where you'll find the options to add your questions.
Click on Page.faq page.
In here you'll find the ability to add a Rich text or Question content block. Use the Rich text block to create separate sections of questions, and the Question block to add an expandable answer box.