To begin, navigate to the Toolbar > Edit with Elementor > Header Dark

Or go to Templates > Theme Builder > Transparent Header > Edit with Elementor. Control the layout, conditions, rules and styles of the header template.

Please check these guides for further information:

Create Headers Using Elementor

Guide to Vamtam Elementor Builder

3. How to edit the logo image

You can edit the column and the Site Logo styles:

To set the logo size, visit the Style section:

You can edit the Logo image, Site title and Tagline in Customize > Site identity:

You can check this guide for more details: Vamtam Elementor Themes: How to edit the Logo image, Site Title and Tagline?