Australia team tryouts

So next weekend I'm trying out for the Australia team. I'm not sure how ill go but I'll go my hardest. I was talking to my hc about what to expect and apparently I'll be running a lot. It's also mid summer over here at the moment.
My main goal is to last the 2 days or pass our trying.
What should I eat the morning of and during the day of the trials? Last thing I wanna do is be sick or run out of puff.
Any other advice would be appreciated. Does any one have any idea of what to expect?