1-Bitrix: site on a subdomain

Good afternoon. As always, there is a problem.
The site site.ru has a subdomain lk.site.ru. Physically, they are located in the /www/site.ru/ and /www/lk.site.ru/ folders. On site.ru there is an old 1C-Bitrix: Site Management 9.0.2, but on lk.site.ru there is nothing at all. How can I make both sites work with the same admin panel?
Thanks in advance.

I used the instructions http://dev.1c-bitrix.ru/community/blogs/howto/336. php: created symlinks, copied access and index, registered hosts and folders in the admin panel, however CMainPage::GetSiteByHost();on lk.site.ru shows the site.ru site id. Which, in general, is logical: for a subdomain. How to overcome this problem?

Answer 1, authority 100%

Here – multi-site on the fingers– this is described in detail. Only I did not quite understand whether this would work with subdomains. See if it helps.