Easiest way to learn is to check out
http://www.apbtconformation.com and also start attending shows and ask questions. Most people are very willing to help newbies.
Toes should point straight forward if they turn out the dog is called easty westy
I believe you mean Topline which is the line along the dogs back which should be slightly sloping not roached or saddle backed
Stacking is the way the dog naturally stands or is positioned in a particular way to show off the structure. Charles described it pretty much. You can see pics and get more descriptions on the link I gave you
Here is a picture of Patcheeno 'Free Stacked' at a show in MD
meaning I didn't touch him or position him that was naturally how he stacked himself
Patch O' Pits Pursuit-O-Perfection
Run Hard at the Rainbow Bridge My Angel Sock-M! I Love You Baby Girl! Now that your Mom Starlit is up there too, please help her learn the ropes, love and keep her company until I can see you both again. Starlit I love you!
http://i14.tinypic.com/2a8q345.jpg