If possible, please send me the full manual of usege

Hi,

Thanks for contacting us here about this extension.

1. Set up call redirect?

You can set redirect all 404 errors to home page by enabling Global home redirect option at Settings > Redirections and 404 tab
Or go to the left menu WP Meta SEO > 404 and redirects to manage the 404 URL.

2, how to set up Social for search engine?

You can see our documentation: https://www.joomunited.com/documentation/wp-meta-seo-documentation#toc-2-6-social-sharing-and-seo-2

Hope it helps!
Cheers,