When installing the theme, you may get error such as ‘the style.css file is missing’. This is due to WordPress not finding the correct stylesheet for the theme, and thus aborting the install process.
The cause is, most of the time, due to uploading the whole package instead of only the theme itself. Often times, our themes will come with additional files and folders, and the actual theme may be inside the download.
All you need to do is extract the package, and make sure the theme files are directly inside the compressed folder:
Package.zip > Theme Folder > style.css