Why won't my sourdough form a shapeable dough that doesn't stick? I'm pretty new to the sourdough game and will admit that I have very little knowledge of the science behind it (hydration, etc.). I have so far tried two sourdough starters to make two simple sourdough boules which have both failed. 

The first was a Paul Hollywood starter and bread recipe. My starter seemed active as described in the book (it would double in size and recede each day when feeding) yet when it came to make the bread my dough would be semi-shapable but would end up sticking to a well-floured (I really mean well-floured...) proving basket and ended up ruining any proving that had occurred rendering it useless.

The second starter I made following this starter recipe from Youtube and this bread recipe from the same person. I decided to go along the video route as I thought I could better see how my dough should look and feel at particular stages. The only difference was that I initially kneaded mine in the KitchenAid Mixer with dough hook to bring it together. For the most part my dough was sticky and wet as expected but didn't quite come together to form the cohesive shapable dough that he seemed to get. I tried adding a bit more flour but it seemed as if I would need to add a lot more to get to the dough that he had. I was able to shape the dough into a ball to place into a well-floured proving basket but again it simply stuck to it when it was time to place it into the oven and lost all air structure from the proving. 

Any ideas what I'm doing wrong?
When I was young and poor I baked all the bread my family of 5 ate, for several years.  I baked yeast and sour dough breads with various flours. 
So some hints: 1. Use good bread flour! King Arthur's or Hecker's brand, if those are not available look for a high gluten wheat flour, if possible unbleached.
2. Get good at making yeast breads first.  Yeast is more efficient than lactoacid bacillus and will make bread rise better.  Once you have made a few batches of nice home style white, then try adding in some different flours.  I used to make oatmeal, rye and Anadamer bread.  All of which are variations on white.  None of them will rise as well due to the lack of gluten. Then add your sour dough to the yeast dough.  Yes, you can get sourdough to rise without yeast but it will take much longer and occasionally fail.  Adding the sour dough starter to a yeast dough will still get you the great sour flavor with the bonus of a better success rate.

3 There is no substitute for kneading.  You generally can't stir enough flour into a dough to make a firm bread, you have to knead in the last couple cups.  Your problem really sounds like not enough flour being kneaded in at the end. Your boule should be smooth and have a dusting of flour on the outside.  You can over knead, if the dough starts to tear rather than stretch just let it rest for half an hour.