just remember..it's not all about PHP when it comes to themes in Nuke
It boils down to HTML and if can you see RAW HTML..not in DW or Frontpage..but HTML code.

Depends on themes also. Some themes use html files...nice and easy to manipulate and change those..but themes that only use a theme.php ok..a little different, but STILL html is embedded..only added slashes for php to parse the html.
Do not worry about $this and $that...those do matter, leave them. Work around them. Those are the variables within in the theme's html etc that calls the news readmore or a link or a usersname or a topicicon.

I hope I helped you.