Ok,
so the theme uses the core navigation function and we included some filter hooks to allow certain aspects of it to be changed:
1. Change the mid_size value ie. the number of page numbers shown between next and previous:
add_filter( 'generate_pagination_mid_size','tu_increase_pagination_numbers' );
function tu_increase_pagination_numbers() {
return 3; // number of page numbers to be displayed
}
2. Change the Next / Previoius labels:
add_filter( 'generate_next_link_text', function() {
return 'Next';
} );
add_filter( 'generate_previous_link_text', function() {
return 'Previous';
} );
But if you require more from the paging nav, and the WP Navi plugin provides what you need – see here for Toms reply on how to integrate it:
https://generatepress.com/forums/topic/first-previous-next-last-navigation/#post-793257