You can either use the WordPress built-in installer and upgrader or you can install the plugin manually.
- Search for 'DKOATED CTA Buttons' through the built-in Plugin menu in WordPress
- Click on 'Install', then click on 'Activate' (or 'Activate plugin')
- Download the plugin and extract the Zip archive locally
- Upload the extracted folder 'dkoated-cta-buttons' to your '/wp-content/plugins/' directory
- Activate the plugin through the 'Plugins' menu in WordPress