https://www.chess.com/lessons/roots-of-positional-understanding/opening-line-of-the-slav-defense
Try and figure out the best way for Black to develop in this position. The first moves were: 1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.Nc3 a6 5.e3 b5 6.b3.
opening lineslav defensechesslessonscom