Intercept the “lost password” action by first redirecting to an existing instructions page

This is straightforward.

1. Hook on init to detect the lostpassword page

2. If the user is not coming from your instructions page (which we defined by adding extra query parameter) he’ll be redirected to your custom page

3. In your custom page add the link to lost password page including the extra parameter we set to skip the redirection.

   add_action( 'init', 'lostpassword_instructions' );
   
   function lostpassword_instructions() {
   
   
       global $pagenow;
   
       if ( $pagenow == 'wp-login.php' && 
           isset( $_REQUEST[ 'action' ] ) && 
           $_REQUEST[ 'action' ] == 'lostpassword' && 
           ! isset( $_REQUEST[ 'skip' ] )
       ) {
   
           exit( wp_redirect( 'http://domain.com/lost-password-instructions' ) );
   
       }
   
   }
   

Now on your custom page, something like that should work:

$url="http://domain.com/wp-login.php?action=lostpassword&skip=true";