What do you want to ask? Do you want to ask whether a product infringes someone else's patent right? If so, you can analyze it without what you said! The product is already in your hand. You have to find someone else's patent. Analyze it when you find it.
If you want to ask, when you own a patent and someone else's product, how do you determine the infringement? Still the same. Just compare the patent with the product and analyze it.
The problem is that in either case, it will be very difficult for you to sue, because you can't find the infringer, that is, you can't find the defendant.