How to setup Arrivals Thread Group(Custom Thread Groups)

I haved used a Jmeter plugin named as Custom Thread Group -> Arrivals Thread Group available at location http://ift.tt/2ovdPM2 for arrival rate simulation. I have a vague idea about its configuration perperties. This is the configuration of my test plan arrival thread group properties:

Target Rate(arrivals/min): 60
Ramp Up Time(min): 1
Ramp-Up Steps Count: 10
Hold Target Rate Time(min): 2
Thread Iterations Limit: 

Can anybody help me to understand clearly what is the usage of all these properties.