Follow the below steps  to set up a new WordPress theme:

Select a theme: Free themes are available in the WordPress theme directory (https://wordpress.org/themes/), and you can also look into premium themes on third-party marketplaces.

Install a theme from the WordPress theme directory:  Go to “Appearance” > “Themes” in your WordPress admin dashboard. Select “Add New” from the menu. You can either browse the available options or you can search for the theme by name. When you’ve found the theme you want, click “Install” and then “Activate” it.

Upload a theme: If you have a paid theme or a theme that you downloaded from another source, you can upload it right away. Click “Appearance” > “Themes” in the WordPress admin panel. To add a new theme, click “Add New” and then “Upload Theme.” Choose “Install Now” after choosing the theme ZIP file from your PC. When the theme has been installed, activate it.

Configure theme settings: Depending on the theme you’ve selected, you may be able to change a few specific settings. On the WordPress admin dashboard, look for a “Theme Options” or “Customise” menu under “Appearance”. Take a look at these options to change things like colors, fonts, layouts, header/footer styles, and more. Make the required adjustments and save them.