Divi Builder (web page editor and WordPress theme)
https://www.elegantthemes.com/documentation/divi/

Divi Update Blog about new features
https://www.elegantthemes.com/blog/theme-releases

Divi Resources Blog with design ideas
https://www.elegantthemes.com/blog/divi-resources

WordPress
https://codex.wordpress.org/Main_Page

Gravity Forms (creates a form)
https://www.gravityhelp.com/documentation/