The whole point behind the Caro-Kann is you are willing to waste a move in order to get the Bishop out, unlike the French, where Black goes full steam ahead, playing c7-c5 in 1 go, at the cost of having a bad bishop. If you know how to handle a bad bishop, I think it is stronger than the Caro-Kann, but if you do not know what you are doing, the French can be lethal to Black in the form of good knight vs bad bishop ending.
So if Black is going to waste the time with his pawns just to get the Bishop out, then really 3...Bf5 makes the most sense against the advance, and thus is why it is by far the most played move, 3...c5 coming in at a distant second and pretty much all other moves are just outright bad. Those 2 moves are Black's only 2 real options.
As I have never used any particular as black, I recently started to look a bit into the theory of the Caro-Kann defense. I found myself a bit lost in the advance variation because I don't really know what to play after 3.e5
What do you think could be a good response and how should I play afterwards?