A CNAME record indicates that the domain is an alias of another domain in the sense that they have common DNS records (not common site content, etc.).

If this record exists for a domain, there must be no other entry for it. Example:

www1.domain.cz.  1800  IN  CNAME  domain.cz.
www2.domain.cz.  1800  IN  CNAME  domain.cz.
www3.domain.cz.  1800  IN  CNAME  domain.cz.
domain.cz.       1800  IN  A      1.2.3.4
domain.cz.       1800  IN  MX     10 mail.domain.cz

Here, the subdomains www1, www2 and www3 are aliases for domain.cz and all of them have an IP address of 1.2.3.4 and also the same MX record. The meaning of the CNAME record is evident – to have the real IP address and possibly other records in only one place and to not have to rewrite them for all domains separately when a change is made.

CNAME DNS records are not available for a second-level domain (e.g. wedos.com). It’s only available for the third-level domain or lower-level domain (e.g. www.wedos.com). For your second-level domain, you need to obtain a server IP address and set it as an A-type DNS record. Reach your provider to get your IP address.