Using Post/Page SEO Settings
In the page or post editor, you will see a new meta box with the SEO Settings button. Click that button to open the settings drawer and make your changes.
Migration From Yoast to Mantis SEO
Once installed, Mantis SEO will check for Yoast. Once it is confirmed that it is installed and activated, you will see an instant migration button. Once clicked, Mantis SEO will automatically migrate all Yoast content.