Activate the schema metabox
To do that, go to SEO main menu then PRO.
Check the iOS toggle associated with Structured Data Types tab.
Check Enable Structured Data Types metabox for your posts, pages and custom post types and click Save changes.
A new metabox will now be displayed when editing a post/page/post type to markup your content, and a new Schemas menu will appear under SEO menu.

Add manual schema to your WordPress post content
Now you have enabled Google structured data types, edit a post / page / post type that you want to markup.
From the Structured Data Types metabox, select a data type like Event.
Fill all the fields correctly.
Save your post.
To make sure everything is OK for Google, use this online official tool.
If you see any error, you have to fix them.
Add an automatic schema to your singular post, page or post type
Read our guide to automatically applied structured data types with SEOPress and improve your productivity.