Optional: Since you're WordPress site is likely empty, and it's hard to create a theme when there's no content, you can download sample content (and import) for development purposes.

No need to touch the theme code. Here's how you can set up a child and block theme in WordPress without the hassle.

How to Create Empty Templates in WordPress. You can customize a WordPress theme to present the content in WordPress posts and pages in a specific format for your company or industry.