Hmm. It's an odd question to ask on a Preppers' forum, when no prepper would ever find themselves in such a situation with such limited kit. But if you're not interested in prepping so much as computer game scenarios then I can perhaps see the attraction.
There are two main answers:
1. The Preppers' Solution
If you're going to be rescued in 28 days then you don't need to worry about food. If you'd like it anyway, then there's a wooded area (and the OP cunningly omits to say what trees or plants, really almost as if it doesn't matter!!!) Failing anything edible there, you make hooks from the bra, use paracord for the line, use seagulls' feathers for the lure or worms for the bait, and fish.
But it doesn't matter if you fail. In 28 days all you need is shelter and water. Shelter is easy - you have a standing wall and a wooded area, and everyone here knows how to make a basic lean-to shelter, especially with a good knife to cut the wood.
Water is the key. Ideally there would be rock pools as River Song says, but really they shouldn't be necessary. Anyone with even the faintest historical awareness will tell you that there would never at any time have been a settlement here without a well. Even if it's long disused and buried with time, you can find it by dowsing or following the deeper shade of green in grass and foliage, dig it out with rocks sharpened by your knife, and bring up water with paracord and mess tin.
Even supposing this isn't a serious question and we have to suppose there's no well, then water is still easy by desalination. You can make fire with knife and ferro-rod, and if no suitable vegetation lends itself to tinder then you rip open the teddy bear and use the kapok. If the kapok is dried with age, then you rub it between your palms to get the necessary oiliness to catch a spark. Once you have the fire, then your mess kit provides the necessary two containers to boil salt water, and the inside of your snugpak smock provides the cold surface for the condensation to form and drip down into your waiting container. Result = potable water.
2. The Other Answer
Well done, Twisted Puppy. You've already insulted everyone on this forum and called them a bunch of spammers in your own 'welcome thread', and that means you've insulted a lot of people I respect. SD says we must play nice, so I've tried to give a genuine answer to your basic 'Idiots Guide' question, but if you posted it just in the hope of making us all look silly then I'm afraid there's only one person looking like a twat round here, and it sure as hell isn't us.
Just saying.