Roundtimer

hey i didnt find any info anywhere on how to do this.
im writing my own kz plugin and all i have left is the timer.. i have no clue on how to get the climbtimer shown as on the roundtimer, any ideas?

Edit: I have a timer system and ive managed to get the timer shown on the round timer, but it goes from 0:00 to 0:59 then back to 0:00 again instead of 1:00

yea ive done that, still doesnt work.
heres what ive got for the timer:

set_task(0.5,"timer",_, _, _, "b") // in plugin_init

public timer() {
	for(new i=1;i<=get_maxplayers();i++) {
		if(is_user_connected(i) && is_user_alive(i) && showtimer[i-1] 
                   && timer_started[i-1]) {
			new cltime = get_systime() - time[i-1], imin
			if((kreedztime / 60.0) >= 1) {
				imin = floatround(cltime / 60.0,floatround_floor)
				cltime -= (floatround(cltime / 60.0,floatround_floor) * 60)
			}
			roundtimer(i, cltime+1)
			
			
		}
	}
}

public roundtimer(id, cltime)
{
	message_begin(MSG_ONE, gmsgRoundTime, _, id) 
	write_short(cltime)
	message_end()
}