What are these numbers ??

Hi ..

1. What do these numbers and letters mean ( as seen in attachment with red arrow ), and why there is 3 rows ?

2. Sometimes i hear them say the engine says this is the best move, where can i see the best move ?

Thanks ....

Those are just variations written out in algebraic notation.

They are ranked suggestions of the best move in the posted position. If you could see the whole position, the engine thinks Qd2 would be best.

That the notation of the engine line. The top line is the engine's top move at the current depth, the second is the second best, etc.

The numbers mean you need to do some of the lessons. They will teach you things like chess notation.

Each row represents a possible line (sequence of moves), the number in front of each line like "+1.08" is the evaluation of the line, meaning how good the line is. Take the first row for example, 9.Qd2 means the the engine suggests white to move the Queen (Q) piece to the d2 square on white's next move. You will need to learn chess notation to be able fo read the notation correctly. 

In your example, 10. Nxd4 h5 means that on the 10th move White captured what was on D4 with a Knight and Black advanced the H Pawn to H5. You should be able to figure the rest of the notation from that.