The Slav Defense is a good and solid chess opening for Black.
Games
The Slav was played by the world champions Euwe, Botvinnik and Smyslov and played by the top grandmasters Anand, Kramnik, Ivanchuk, Lautier and Short. The theory of the Slav has grown and became quite extensive.
It starts with the moves: 1. d2-d4 d7-d5 2. c2-c4 c7-c6
It is classified as closed opening. In the Slav Defense the diagonal c8-h3 will be kept open to be able to develop the bishop on c8 to f5 or g4 which would otherwise be locked in if you play e6 instead of c6. Black prepares to take the c-pawn (dxc) and protect it with b5.
Consider the following variations:
The Exchange Variation 3. c4xd5 c6xd5 If white exchanges the pawns he has given away his opening advantage. The position is even. For that reason the exchange variation is seldom played in grandmaster chess.
Study this straightforward and logical approach.
The Open Slav: 3. Sg1-f3 Sg8-f6 4. Sb1-c3
Attention: Don't play now 4. .. Lc8-f5? as this will be refuted by 5.c4xd5 cxd5 6. Dd1-b3 b7-b6 7. e2-e4!
Correct is: 4....d5xc4 5.a2-a4 Lc8-f5 6.e2-e3 e7-e6 7.Lf1xc4 Lf8-b4 8.0-0 White has just a small space advantage.
If you are a beginner I do recommend the chess variation below for Black as it is a simple setup and all your pieces are out in the open and working. Study the games and try to understand how the game is played after the opening is finished.
Black has developed his queen knight first and waited with castling. Then White traded off bishop at g6 and opened h-file. Black used the h-file to start a deadly attack and castled queenside!
There are a lot of other variations as you will see when you replay the games, but study first the above mentioned variation which is fairly easy to understand and logical.