Custom Post Type

Hi I have installed this plugin and it works onWordpress 4, I have a custom post which uses the author meta box drop down and with 60,000 members it take forever to load the plugin.. I tried to speak to the developers of the plugin but they just dont come back to me, so I search and found this plugins…

How can I add this meta box to my custom post type..

Thanks

https://www.ads-software.com/plugins/authors-autocomplete-meta-box/