YAPB – I had to install it, what to do about?

Hi everybody
Let me premise I am a novice at WP, please bear with me if my issues may look naive…
I am using Autofocus+ theme on my site and for using it I had to install also the YAPB plugin.
Which is described in its website’s author as a marvellous tool for blogging, but I don’t understand what I can do with it.
I have a YAPB Image section in my Edit post interface but it’s not clear what will result after using it.
BTW, can I use it to create thumbnails for a grid layout Archive page?
thanks
Fabio