$ns color color-id defines color index for nam. Once specified, color-id can be used in place of the color name in nam traces.
$ns trace-annotate annotation inserts an annotation in nam. Notice that if <annotation> contains white spaces, it must be quoted using the double quote. An example of this would be $ns at $time ''$ns trace-annotate ''Event A happened'''' This annotation appears in the nam window and is used to control playing of nam by events.
$ns set-animation-rate timestep causes nam to set the animation playout rate to the given timestep value. Time is in seconds, with optional prefixes (for example, 1 is 1 second, or 2ms is 0.002 seconds).