We are really sorry to say that, installation & customization services does not include item support.
However, we could provide you some suggestion based on your inquiry.
First of all, you have to install your own WHMCS (by purchasing a WHMCS license) anywhere in your hosting server. After then, you could connect your WHMCS in WordPress using whmcs bridge plugin OR
you could install & use the provided WHMCS Template in your WHMCS to use separately to get all of the things like our demo. Moreover, you need to link up all of your products/services (buy now link) to your WHMCS.
Moreover, please learn more our full support policy (item support includes & not includes), here https://www.themelooks.com/support/support-policy/ before post a topic or ask for support.
Best Regards,
ThemeLooks Support Team