Ok your process allready looks quite big and complex.
You should definetly start out with the basic example process from the tutorial and see if you can get this one running. Afterwards you can extend this process until it matches your use case.
With a quick look over your .bpmn-file:
You marked the task “Approve Process” as Multi Instance but did not set any loop variables. That definetly is an issue which leads to the point, that Camunda does not deploy your process. Furthermore you should use start- and end events in your subprocess. And all the tasks in your process should be combined with sequence flows, otherwise they do not make any sense. And for simple processes to get your hands on the engine you should try to start your process with a blank start event and not with a signal start event.
My advice is to model the process from the getting started tutorial and see, if you can display that one in the cockpit.