Hi,
Whenever you are creating the Http Request Data Collector, you need to give the specifc HTTP Parameters as (display name and Parameter Name).eg: display name could be arrayDisplayName and Parameter Name could be array.
you can also collect the cokkies value etc as per you requirements.
if you want to collect the data related to the parameter of your method, then you can crete the MIDC (method invocation data collector) on your class and method.
Thanks,
Ashish.