How to find out the admin panel of the site and the FTP site?

Question

Web development

Good site time everyone!
There is such a site - plastok.ru/ .
This site needs to be edited and transferred to another hosting. The problem is that the FTP address is not known and the admin panel too. Known only Login and Password from FTP and admin panel.
There is no connection with the previous developer of the site. And the site was sold to new people and needs to be edited and transferred to another hosting.
Can you please tell me how to find the admin panel of the site and the FTP address?

Answer 1

ftp://plastok.ru
And by connecting to FTP, you can find the admin panel by viewing the site code.

Answer 2

ftp has already been written, admin panel, randomly poked:
https://www.plastok.ru/admin/

Answer 3

1. We find out the IP address of the site (for example, with the ping command).
   
2. Find out who owns this IP address (whois, traceroute). We already know who the host is.
   
3. We go to the hoster's website - there are his contacts.