Examples will probably help : In every examples also at first press 'New action', select some Action name and at last press 'Change hotkeys' and assign a hotkeys combination to your action.
Pick 'Command to execute'/'URL to execute' and enter the command, then press 'Autodetect'. Pick the right window. If e.g. the title is not always the same, set it back to 'not significant'. Press 'Ok' and the configuration is done.
Command to execute : rm -f ~/trash
URL to execute : '<your_home_dir>' Don't run if window title exists : file:/<your_home_dir> Don't run if window class exists : kfm kfm
Command to execute : netscape Don't run if window class exists : Navigator Netscape
For some reason I can't find a shortcut for maximizing a window in the standard KWM global shortcuts, although there is a IMHO not so useful shortcut for minimizing a window. Hmm, no problem :
Command to execute : kwmcom winMaximize