White pawn is allowed to move to the fourth horizontal from the
second, and black pawn is allowed to move to the (N-3)-rd horizontal
row from the (N-1)-st.

Could anyone explan it more clearly and fully ? Thanks a lot !!!

> White pawn is allowed to move to the fourth horizontal from the
> second, and black pawn is allowed to move to the (N-3)-rd
horizontal
> row from the (N-1)-st.
>
> Could anyone explan it more clearly and fully ? Thanks a lot !!!

It means that according to the rules of chess the pawn may(and may
not) move in the first time by 2 fields ahead, not by one as usual.
It is olny the first move, no more. Understand now?
  Good Luck.