Caro Kann Classical variation

don't let queen e2 be played

And how would I do that?

20. ...f5 is correct. Black is fine there. To further understand the position and how to defend it put it in an engine and see for yourself. White has no attack and black can get an advantage even if played correctly.

One example would be:

Vincent, try downloading, or buying, a ChessBase Frtiz Opening Trainer. They have some wonderful CDs on lots of openings, I did see the caro-kann before.

You're a video creator yourself, am sure that you prefer studying from videos as well that's been made by some strong GMs. Perhaps it's better than buying a book nowadays to some.

I could tell you to use the lines in ChessBase, but that's not the best way to learn, as it doesn't have any real explanation, just statistics.

I hope that I did help, and sorry, but am not a Caro-kann player.   

This response may be several years later, judging by the original poster's date, but to whom it may concern. The answer for black is Bf5 ( Bishop to f5). A great book to study is "Winning Chess Openings" by Yasser Seirawan. It includes the Caro-Kann, in its many variations. It shows the best moves for black, and for white, as well as the reasoning behind them. It is a very comprehensive book on practically every opening one can think of. It is an invaluable source of opening knowledge, which I refer to regularly. It even includes the rarely used  or potentially dangerous openings used by Bobby Fischer, the Benoni, and Najdorf. I highly recommend it. I trust my answer proved helpful to someone. Yasser Seirawan also has other books in the "Winning Chess" Series. Check it Out! Ciao!!!