新手试图理解.h文件中的多个@interface

I'm a newbie, trying to take a freeware application last updated in 2008 and since (apparently) abandoned by the programmers, who haven't responded to my emails, and both update it for the current MacOS and also create a version for the iPhone. I imagine this is going to be a long and somewhat nightmarish process but I'm looking forward to learning.I'm a newbie, trying to take a freeware applica