Differences among Ad Blocks, Ad Zones, Ad Places

I am new to Simple Ads Manager, and wondering what are the differences among the Ad Blocks, Ad Zones, Ad Places. What they exactly denote?

As per my common sense, I can assume that:
* An “Ad blocks” is the area where I can show multiple ads.
* An “Ad places” is the Advertisement, I want to show on the site.

But I’m confused with the whole idea. Please make it clear.
Thanks in advance.

https://www.ads-software.com/extend/plugins/simple-ads-manager/