It's through orders in council and the publishing of the names.
To answer the second part of your question, on how we decide, this is done on the basis of what we want to accomplish. Again, that's why it's a flexible tool, but it's not the only tool that we have when we want to send a message or to restrict the ability of a country to act maliciously.
In the case of Russia, for example, we have close to 2,000 individuals and entities listed, and it pretty much covers all the categories you included below President Putin. It's the individuals who are close to him. It's the individuals in the Duma. Hundreds of them are listed, because either we know they are complicit—and we know this because of their voting record in the Duma—or we know they have the ability to change things. We want to exert pressure on them to apply pressure on the regime. It's also the oligarchs, because we know of their proximity to the regime. First of all, there's the fact that they've gained from a criminal regime, and second, they have an ability to put pressure on political decision-makers.
It's all of the above.