Go to Studio > Build and build a flow for your use case.
At whichever point of conversation you want the bot to display the payment link, include the integrations node. For that, drag the node connector, go to Integrations > select the payment gateway you have integrated.
In the integrations node fill in the following fields:
Account name: Choose the payment gateway account. If you have only one account, the account name is automatically populated. If you have multiple accounts, the first account added is auto-populated. Select the one you want to use at that moment.
Action: Choose the action as Generate Payment Link.
Fill in the corresponding fields.
Store the JSON response of the payment node in a variable and display the API response in a message node for the users to click the payment link and make a payment.