Start Process from Bean shell

I have stated process via beam shell load bind using ,

WorkflowManager workflowManager = (WorkflowManager) AppUtil.getApplicationContext().getBean("workflowManager");
String processDefId = "app_yyyy_portal#126#emp_data";
Map variables = new HashMap();
variables.put("account_managers", "xxxx");
//Start a process with existing record
WorkflowProcessResult result = workflowManager.processStart(processDefId, variables, "xxxx");

Process is created but how to pass form field values in it?