Step 1. Download the CyberSource Unified Checkout plugin in your Patreon Dashboard
https://www.patreon.com/posts/cybersource-142294052
Step 2. Extract the file zip archive in your computer
Step 3. Install your CyberSource Unified Checkout plugin in WordPress
Goto in your WordPress admin dashboard menu plugins > Add New
Next Add Plugins using Upload Plugin button
Upload the CyberSource Unified Checkout plugin zip file
Activate the CyberSource Unified Checkout plugin