You should probably stick to what you know. The first thing you have to realize is that water doesn't run uphill. Using that simple bit of information, I can find a spot that is on a slight rise thus preventing water from running in. It's not that complicated. As far as building the shelter fast goes, that is also a simple proposition. All you need to know is how to tie knots. Of course if you don't know that water doesn't run uphill, you might face the boughs the wrong way and flood the site anyway. The thing to remember is, that to build a shelter that works, you only have to tie four knots. If you can keep the corners of the frame together, you're halfway there. Once you get the four knots tied, assuming you have gotten that far, hoist it up in a tree, assuming you are actually in the woods. The last step, assuming you have made it this far, is to cover it with branches. As long as you point the branches downward, the water will run off. The branches will provide their own structural support so no new knots are needed. If you have problems with this, then a BOB probably won't save you. Maybe you should walk down to the rangers station and have a cup of cocoa. Remember, four knots does not take forever. It's just like tying your shoes twice. How long should that take?