Teacher Prep is just seperating the cards (we used to have to cut them apart) at the beginning of each Level, and the initial process of putting the magnets on the back of the tiles, if you go that route. There is no prep for each lesson, unless you need to remove/put up tiles because you’re working w/ more than one dc, which I do.
The time for the spelling is just the 15 min or so that you spend w/ your dc. Use a timer even. Sit down, open the book and follow the step. I found for the older dc, most steps were about 15 – 20 min and we would just finish it up at that time. For the youngers, it might take 2-3 days per step, occasionally more depending on the dc. There is built-in review which should be done each time before starting on the new material, even mid-step. You can even set the timer for just 10 min, giving yourself a few min to finish up that particular section.
Realize that by finishing a step does not mean that every little thing w/in it was mastered. (One point that I had a hard time swallowing w/ the Duffy review.) The lesson is for introducing and working w/ the dc. Once that is done, you move on to the next. You do not stay on a step continually until everything learned is mastered completely, this usually takes time for anything. Obviously, for younger dc or those w/ particular needs, it might take longer to get through the lesson or you might choose to spend more time on that concept. But, you will NOT spend “months” on one step (except for those rare situations).
Think of it this way . . .
You teach a child their math facts. They understand the concept and what it means then practice it, but they do not know the facts by heart. Over the next few days/weeks, you review those w/ flashcards. As they go through the cards (Review pile), you set the ones they get easily aside (Mastered pile) because they’ve learned that fact. Each day it gets better, quicker, and less that are needing to be reviewed. Every so often, you will take all those Mastered facts and do a quick run through. If there are any that they stumble w/ or have to think about too much, you just pop them back into the Review pile.
I did start at the beginning w/ my oldest ds, he was just 13 when I found AAS. Yes, it was easy at first and we went through very quickly. But . . . the review was very good for him, we learned the process, and I learned how to word things to help him remember for himself when he came to me w/ a spelling question. It allowed me to help him think it through.
You could start w/ Level 2. On the AAS site, they give you a few questions to ask yourself. If you do this, I would suggest you pick up the Phonogram cards that are available to purchase seperately. These are the only cards from the first level that you might come across to enough of an extent to have them on hand and they can be used in place of the Sound cards. The other cards will be in the materials packet. (Another point Duffy had poor info about.)
HTH
K