Create a New Sales Order PHP Example

Hi,
Any one can share the sample PHP code to create a new sales order with multiple items for a customer, if customer does not exist, then create the customer first?

Is there a function that when I try to create a customer, it will check if this is a dup customer based on my system dup customer rule setup, only create when it is a new customer?

This code always create a new customer, does not care about dup.

//create Customer record
$customer = new nsComplexObject('Customer');
// set fields
$customer->setFields($customerFields);

// perform add operation and store nsWriteResponse object in $addResponse variable