How do you satisfy the BY part of a license, the attribution of the original creator?
If a creator specifies a specific way to attribute them, that is what the user should use.
If a creator does not specify a specific way to attribute them, the best practice is to use the TASL approach:
Title - what is the name of the material?
Author - who owns the material?
Source - where can I find it?
License - how can I use it?
If there is no title given, then none is needed.
The author could be an actual name, a company name, or a pseudonym.
The source will be at least a URL. If a DOI or other identifier is used, include that as well.
Note the license under which the work is offered. Include the version if it is given.
Satisfy the conditions in a reasonable manner, but don't make the attribution overly complicated. There is no single right way, but the result should be as clear as possible. Attribution is required for any licensed work not in the public domain.