Typically, your X-Cart 5 store will have the X-Payments connector module installed and enabled from the very start:

If not, you can install it from the X-Cart 5 Marketplace.

For instructions on how to configure the connection, see Connecting X-Cart 5 and X-Payments.

Important: Please be aware that the X-Payments connector module for X-Cart 5 has no support for the Not finished orders module; for this reason, regardless of the module settings, Not finished orders will not be created when payment is made via X-Payments.