(show_hud_timer [BOOLEAN])
(pause_hud_timer [BOOLEAN])
(hud_set_timer_time [SHORT] [SHORT])
(hud_set_timer_position [SHORT] [SHORT] [HUD_CORNER])
For future reference, opening the scripting bible, and pressing ctrl + f will open up a search window. Type in "timer", or any keyword that you think will lead you to that script.
As for Hydrogen's post, he's referring to
http://hce.halomaps.org/index.cfm?fid=3424Open d40.hsc, and do ctrl + f to search for the command, and find the parameters that might be beneficial to your cause.