Help circular array of a sketch

I am doing self-paced training spse_01510 drawing E (sketching). I am stuck on doing a circular array / pattern. Can anybody explain how to do it?

Sketch is a simple circle of diameter 8.
I need to create:
a circular pattern with pattern radius of 42.5,
sweep angle 180 degrees,
and a fill angle between instances of 15 degrees.

1. Do I do this in synchronous mode or ordered mode?
2. Steps to do this?

Thanks for the help