Connect and set up the module

Go to the OpenCart admin panel.
In the side menu, select Modules/Extensions → Modules/Extensions.
In the Select extension type section, select Payment.
Find the Yandex Pay module on the list and click + to enable it.
Go to the module settings. To do this, click the "pencil" icon to the right of the module name.

Module settings

API key: The key for request identification. To manage the keys, go to the Yandex Pay console.
Merchant ID: The ID that the merchant receives when they register in Yandex Pay.
Merchant name: The store name in Yandex Pay.
Test mode: Enable test mode to debug the module. If this option is enabled, money won't be debited from the card.
Mode: Placement options for module components (buy with one click or pay on the order creation page).
Take into account the number of items in the cart: The maximum allowed number of items in the cart.
Allow payment on delivery: Allows payment on delivery in the Yandex Pay Checkout module (buy in one click).
Allos comments: Allows the user to enter comments in the Yandex Pay Checkout module (buy with one click).
Allow discount promocodes: Allows the user to enter a discount promocode in the Yandex Pay Checkout module (buy with one click).
Enable Split: Allows the user to pay in installments.
Enable Yandex Delivery: Allows the user to order delivery.
Status: Enable or disable the module.

Match the order statuses according to the store settings. Recommended statuses:

Pending payment: Pending.
Payment for the order has been authorized. The funds on the customer's account have been blocked: Processing.
The order has been paid for successfully. The funds have been withdrawn from the customer's account: Completed.
The payment has been canceled (voided). No money has been charged: Canceled.
The order money has been refunded: Full refund.
The order money has been partially refunded: Refund.
The order payment has failed: Failed.

Set up the button design:

Selector for the product/cart/order: CSS selector where the button must be placed in order to be displayed.
Display type: The way the button is displayed. Learn more in Branding rules.
Button width: Button size. Acceptable values:
- Automatic: The script sets the optimal button width automatically.
- Maximal: The button fits the block where it's placed.
Top/bottom/left/right margin: The margins around the button in pixels.
Free CSS: Appearance settings for advanced users (developers).

Pickup: Create pickup (depot) points for the store.
Deliveries: Add the missing data for delivery. The module automatically checks which supported delivery modules the store has installed.
Log: Enables the collection of error data. This is necessary for technical support.