First, follow this guide to install SEOPress for MainWP add-on.
Apply global SEO settings to your sites
Login to your site where MainWP Dashboard is installed.
Go to MainWP, Extensions, SEOPress settings page.
From the right column, select the site whose SEO settings you want to change and click Load Settings button.
Then, use the different tabs like Titles and metas or XML sitemaps to edit your global SEO settings for the selected site.
Once you are satisfied with the new settings, do not forget to apply them by clicking Apply Changes green button from the right column.
Import / export your SEOPress configuration from a site to another
Save time by importing your SEOPress configuration from another site in seconds.
Export SEOPress settings
From MainWP, Extensions, SEOPress, Tools tab, click Export button.
Select a site and click Export Settings button.
Wait a few seconds to see your settings in JSON format appear in the right column.
Copy the settings (click on the textarea field, CTRL+A, CTRL+C or CMD+A, CMD+C on MacOS).
Import SEOPress settings
Then click Import button.
Choose the site where you want to import the settings.
And click Import Settings button.