Zeroy shows us how to create a timer for triggering events

Dragon Rising: Create a Timer for triggering Events

When you add a timer it will count from the start time down to 0 at which point the function onTimer_TIMERNAME(name) becomes usable.

Say you want to have Echelon1 moving from one location to another 5 minutes after your Player and his Fireteam entered triggerzone1:

function onEnter_triggerzone1(zoneName, UnitName)
	OFP:addTimer("timer1", 300000) -- 300000ms = 5mins
	hours, minutes, seconds = OFP: convertTimeToHMS(OFP:getTimer("timer1"));
	OFP:displaySystemMessage("The time: " .. hours .. ":" .. minutes .. ":" .. seconds);
	OFP:disableEvent("onEnter_triggerzone1")
end

function onTimer_timer1(name)
	OFP:activateEntitySet("Echelon1")
	OFP:move("Echelon1", "waypoint", "ADDTOFRONT")
end

function onTimer_timer1(name)
	OFP:setObjectiveState("Objective", "COMPLETED")
	OFP:removeTimer("timer1")
	OFP:missionCompleted()
end