These will be your track markers on the day, mostly on the bike stage as there are a few tracks that criss cross over each other, and we don't want you taking the wrong turn! In addition to these, make sure you check out the 13km Bike Course video which shows you exactly where the track goes.
I don't imagine it'll be difficult to stay on course for the run stages, but if I can find some stakes then I'll probably put a few out with these 'ere markers on them. It'll be more for encouragement than direction I guess, but whatever helps!
Hope training is going well :)