To customize some of themes here basic guide
If you want to replace the default loading text with a logo or custom name, you can do this directly from the Preload / Loading Section.
To customize the preload behavior, first navigate to the Section Preload in your project settings or page structure.
This section controls what appears on the screen while the page is loading.

Inside the preload loading section, you’ll see a Heading (Custom) element. This element is flexible and can be used in two ways:
If you want to display a brand name or custom text:
This option is best if you want a lightweight, fast-loading preload.
If you prefer using a logo instead of text:
Make sure the logo is optimized (SVG or compressed PNG) for better loading performance.
After making changes:
This ensures the loading screen matches your brand identity perfectly.