All header options can be found by going to WP Dashboard -> Appearance -> Customize -> Header Options.
Change Logo
To change the logo navigate to the logo options, WP Dashboard -> Appearance -> Customize -> Header Options -> Logo. After adding your logo and adjusting the settings click on publish.
Main Header Options
By going to WP Dashboard -> Appearance -> Customize -> Header Options -> Header Options you will be able to change the header logo and enable/disable sticky header.