You might want to read more before tackling this on an Autoride truck. You need to understand how this all works before diving in like this.
The Autoride links tell the truck whether to put air in the rear shocks or not -- and it does this when it senses that the rear is lower. (If you put a bunch of stuff in the rear, or are towing a boat, etc., it'll try to raise the rear so that the truck sits level again.) With no links in place, or the factory links in on a lowered truck, the compressor is going to keep the rear shocks filled with air. It won't let the truck drop. That's why you need to shorten the rear links so that the truck doesn't see that any drop to the rear has occurred.
The length you need your new links to be is something shorter than the stock links. You're going to have to mess with it to get it right. Shorten them a lot, and the truck will never raise the rear -- and that's fine IF the truck sits perfectly like that. Otherwise, you're going to have to mess with the link length to let just the right amount of raising to occur.
You can't just swap out the shocks for non-autoride ones, unless you want constant codes and warnings.
I'd also be more than a little bit concerned if your installer doesn't recognize what shock extenders looks like/where they go. I'm not trying to be disparaging -- I just think you ought to have a drop installed by someone who knows a decent amount about these things.
It's all been discussed here before. Keep asking questions, but check out all of the threads on lowering in the meantime. There's a lot to know.
Good luck!