Direct buy problem

I want to “buy now” the domain that can be purchased. But I couldn’t figure out the link. At most it goes to the whmcs domain search screen. What I want is that when the link is clicked, it is automatically added to the whmcs cart and taken to the “https://hedefhosting.com.tr/whmcs/cart.php?a=confdomains” page. But how, how, how.. :'(

The page I need help with: [log in to see the link]