Adding Custom Header

Hello, everyone.

I’ve done a search and can’t seem to find a fix anywhere for my problem. (Maybe my eyes are just tired.)

I’ve uploaded a WordPress theme (it’s one of those that doesn’t allow you to “change header” under Appearance) and adding a custom header is proving to be a Herculean task.

I am certain there is a way to make this happen and I’m sure some of you have encountered the same roadblock.

Help.