If you want to show only specific agents or services to your customers when they book their appointment, you can simple set show_agents, show_services, show_service_categories and show_locations attributes of the [latepoint_book_button] or [latepoint_book_form] shortcode with a list of agents or services you want to appear on the booking form. You can find agent, service or location ID either in URL on service/agent edit page as last parameter on the edit form in admin:
Example Usage:
[latepoint_book_button show_agents="3,2,4" show_services="2,3" show_locations="1,3" show_service_categories="1,2"]