Not to discourage further discussion, but I discussed Russian war plans and the 1812 invasion itself in my comments here. The main thing I would add for context is that Napoleon invaded to enforce the Continental System; all states allied with France would cease trading with Great Britain. Russia had agreed to this at the Peace of Tilsit, but reneged on the deal, both for economic reasons and because Tilsit was seen as a humiliation. Feel free to hit me with any follow up questions; your submission is a bit open ended, so let us know if there's anything specific you want to know more about.