Subdomain for WordPress URL

Not sure precisely how to ask this and I’ve done a small bit of research about the topic but have come up short. I’m trying to have blog.domain.com of my website (Apache) access domain.com/blog of my WordPress install. Obviously this is a virtual WordPress directory so I can’t just point the subdirectory because it doesn’t actually exist except within WordPress, so how would I go about making this work? Is there a tutorial? Thanks very much for any help.