Server Side

1.Save the below assigned apiEndPoint value at your server for payment options.

String apiEndPoint = "/v3/merchant/payment/options";

Call Get Payment Options API. Refer this link for more details.
Select one of the API keys shared with you and note it's index. Refer this link for salt key value and salt index credentials. Construct the checksum at your server as follows:

String checksum = sha256(base64Body + apiEndPoint + salt) + ### + saltIndex;

App Side

Collect payment options API response and display payment option modes on the user interface.