after studying the advanced briefly i came to certain conclusions. for instance, after 1.e4 e6 2.d4 d5 3.e5 c5 4.c3, that the best move for black is 4...cxd4!

this gives a clear plan for black which is to play for the pawn on d4.

it is better than the b6 lines or all other lines which lead to insipid play.

now play can continue 

[Event "?"]
[Site "?"]
[Date "2022.03.11"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]

1. d4 e6 2. e4 d5 3. e5 c5 4. c3 cxd4 5. cxd4 Ne7 6. Nf3 Nf5 7. Bd3 Nc6 8. Bxf5
exf5 9. Nc3 Be6 *

and black has a favorable imbalance. in certain positions he plays g5 and blow white off the board.