After updating my website to WordPress 5.0 I cannot use Page Builder anymore. How can I get it back?

WordPress 5.0 introduces a new editor for the content named Gutenberg.

We’ve been using the Page Builder by SiteOrigin plugin for years in our themes and all our themes use it. While we migrate our themes to be Gutenberg-compatible, you can get the old classic editor experience with Page Builder by installing the Classic Editor official WordPress plugin.

TIP: If you’ve never installed a WordPress plugin before, here is a quick guide.