The Site Name is for adding the website's name. This is what appears on the top most part of your website. If you don't want to add anything here, you may leave it blank.
When you hover your mouse cursor to the banner, you will see the other customization options you can use.
You can use an image as a banner for your website. Just click on Change Image and upload your chosen banner. Use any banner templates from graphics editor like Canva to design a banner that fits your site.
Header type is for selecting how you want to view your banner. The size is based on the sequence: Cover, Large Banner, Banner, Title Only.
Hover your mouse cursor near the Site Name, you will see the Add Logo option. According to Steegle.com, Google recommends to upload a logo with at least 112 pixels height.
When you click the gear icon ⚙️, you will see the other site settings like options for navigation view. You can change it to top or side. You may also change its color.
In the next page, we'll discuss how to add contents. How to Add Contents