well, you are asking for some really complicated and detailed advice.
Let's just deal with the scent exercise.
I teach this with specially made scent articles. They are made similar to the dumb bell, but smaller, and of leather or metal. The dog must have a VERY good and enthusiastic retrieve and pick up of the DUMB BELL.
Once the retrieve is very solid, I teach the hold, pick up, and retrieve with the METAL scent article. You could use whatever object your dog must find in the competition. Just make sure you have trained and reinforced the hold, pick up, and retrieve with this article BEFORE you start with the scent work.
When the dog is very strong in the retrieve of the article you will be using for scent work, take 2 identical objects. One well scented by you, and the other with NONE of your scent on it. Handle the unscented article with tongs to keep any scent from getting on it.
Put out the scented and the unscented articles, side by side, about 12" apart.
Set the dog up in front of the SCENTED article, and send as if for a regular retrieve.
If the dog selects the scented article, immediately CLICK or say your marker word, call the dog to you, and praise and reward.
If the dog selects the INCORRECT unscented article, simply refuse to take it from the dog. Put your hands behind your back, smile, and wait. If you need to help the dog, you may give the retrieve command again, but give the dog some time to work out the problem.
Most dogs, esp those who have been trained positively to shape the retrieve exercise, will quickly go and select the other (correct) dumb bell. CLICK, praise and reward.
If dog has an excellent retrieve, and has been properly reinforced on the scent articles, you can have a dog doing the entire pile of scent articles as they do in the AKC Utility Exercise in a week or two.
I do not ever use the tie down method. I have found this method makes things SO much clearer to the dog, and they learn to really enjoy this exercise.
I used it as a parlor trick all the time with my old bitch. I would have everyone put their car keys in a pile with mine on the bottom and she would go find mine every time.