How to use custom attributes

Sorry if this is a stupid question but despite searching I am stumped by how to set/ read custom attributes.

Have you read the article in Hazel's help?

No, I searched for Custom Attributes but nothing came up …. hence my post.

However, knowing that there was such an article, I poked around a few potentially related topics and have now found it. Think the Index is a bit lacking.

Yeah, that part is a problem with Apple help's indexer. I'll see if I can add more keywords to make it work better in the future.