> For sending the events I am not sure how to do this in the correct way. 

bm_compose_event()
bm_send_event()

You can use bk_init (better bk_init32) to create a bank structure inside an event, but that's not mandatory.
Nothing prevents you from putting a JSON string into your event, as long as the midas even header (created
via bm_compose_event() is correct).

Best,
Stefan