What do I do to denot an edition of a book as an ARC?

[Lyd's Archive (7/'15 to 6/'18)]

what I said.

[Krazykiwi]

I'm not sure in what context you mean, so:

When adding it as an edition to GR?
Add it in a librarian note, since ARC's are the exception to moving ISBN's it will save time on publication if you already marked it. Other than that, nothing special. Add it with all the info and cover as usual. Just make sure you add the cover you actually have on the book though, which may or may not be final, and may or may not even have something like "Proof copy" or "Galley" or "ARC" printed on it, depending what publisher it's from.

When reviewing it?
Disclose that you received it free for review. The publisher may have other requests, such as to note that it was prepublication and any quotes you used may be subject to change, they probably gave you any instructions in that regard when you got the book though.

[Lyd's Archive (7/'15 to 6/'18)]

thanks

[rivka, Former Moderator]

When adding the book record, it's also a good idea to indicate Advanced Reader Copy (or similar) on the edition line.