Log in your WordPress admin area, go to Plugins and click Add New:
Enter 'YD Gateway 2Checkout for WooCommerce' in the Search field → Click Install Now:
Otherwise, you can go HERE and download plugin directly. When it's downloaded, go to the Plugins tab in your WordPress admin area. Click the Add New button, then Upload Plugin, choose a file to upload, and click Install Now.
The plugin will be installed from the uploaded file. Now you can activate the plugin.
Now go to WooCommerce → Settings → Payments → click 2Checkout in the popup with Credit Card/PayPal → Manage:
Activate 2Checkout as your payment gateway. To be able to place demo sales to see the purchase process as a buyer would, enable Demo mode.
Copy your Merchant code (Account number) and Secret Key from your 2Checkout Dashboard → Integrations → Webhooks and API:
Paste them in your WordPress admin area:
You may add Title (it will be shown instead of the default ‘Credit Card (2Checkout’) and Brand Name as well.
Copy the value of the IPN URL field and paste it to your 2CO account → Integration → Webhooks & API → IPN Settings.
To make data exchange faster, please click the 'Edit' icon near the IPN URL and tick on the 'Allow concurrent requests (faster notifications)' box:
Finish by clicking Save Changes.