At the most basic level, doubles are often used as decoys to keep top govt officials safe. A double goes out the main door and into a car where he is exposed to an attack. Meanwhile the real one goes out a back door. But doubles are also used for nefarious reasons including tricking the people. When Hilary was shoved into a van at the 911 ceremony, the woman who came out a couple hours later was not her. They needed to present Hilary as well and fit and able to continue to campaign. But we can also see now where doubles are covering up for Biden. The real one is not capable of doing much of anything, but they have to project that he can. Hence, you have a double in a mask signing an EO with his left hand while in fact he's right handed. And then there's the whole idea that some of these people have been switched out permanently with a double. That's another whole topic. And perhaps that's more of what you're looking for. I thought I'd at leaat explain the basic idea for using doubles.