Header change?

Hi,
I’m struggling with WP, but I’ve decided not to go with a drag and drop
type builder. I thought they would be great, but the the cluttered menus and small boutique feel kind of turned me off.
So, I’m trying to change my header image. I have kubrick running. When I
try to do a custom header, as in a video tutorial I’ve watched, I dont
get the option of searching in my picture files. I just get an
“update header” button. This is no help.
Is there an easy way to acomplish this change? It would be very reassuring at this point. I do not know code, but would be willing to learn. I just like quick remedies. Or add-ons that might speed things up.
Any help would be great….