Rename

I’ve got my thicko head on today so please bear with me. I’ve been looking at the rename-wp-login plugin and am having a little trouble understanding it. If it renames the logon page, how can anyone access the site externally.

If it re-directs to the original login how can it protect against brute force attacks?

Can someone give me an idiot’s guide to how this works please as I would like to use it.

Thanks

Jim