How to Install a Theme in WordPress
On your WordPress dashboard, go to Appearance > Themes.

Click Add New > Upload Theme.

Upload the theme file in .zip format and click Install Now to start installing the theme.
Once it’s done, click Activate to apply the theme.

You can also click Live Preview to see how it looks first without activating the theme.

Once you’re ready, click Activate & Publish to activate and apply the theme.