To be able to accept CASHU as a payment method through a Merchant Account, you will need first to create a Merchant Sandbox Account. The Sandbox Account will allow you to test the integration process and get familiar with the merchant account settings and preferences.  When you are all set with the integration process and settings, and after making at least one successful test transaction, you will be able to change your account type from a Sandbox Account to a Live Account after completing all the needed documents with the Merchants Team.

To create a Sandbox Account, please use the below link.