2K5/q5QQ/4k3/8/8/8/8/8 b - - 0 2

KR1q3Q/8/6k1/8/8/8/8/8 b - - 0 2

K7/2r5/8/3R4/7k/8/6Q1/8 b - - 0 2

K2R3Q/5k1b/8/8/8/8/8/8 b - - 0 2

K1k1n3/8/8/8/8/5R2/6Q1/8 b - - 0 2

2k5/B7/Q2K4/8/8/7q/8/8 b - - 0 2

K7/B6b/4k3/8/8/8/8/Q7 b - - 0 2

K1n3Q1/2k4B/8/8/8/8/8/8 b - - 0 2

3k4/8/2NK4/8/Q7/8/8/6q1 b - - 0 2

K5N1/1Q6/8/5k2/8/3b4/8/8 b - - 0 2

KQ2n3/8/2k5/8/8/8/8/N7 b - - 0 2

8/5q2/Q5k1/P7/8/8/7K/8 b - - 0 2

6qk/Q4K2/8/8/8/1P6/8/8 w - - 0 2

Q7/3q4/8/3K4/8/2P5/7k/8 w - - 0 2

8/2Q4K/8/1q6/8/3P4/8/7k w - - 0 2

1k6/6r1/2K5/8/8/8/4q3/2Q5 w - - 0 2

qk1K2Q1/8/6n1/8/8/8/8/8 w - - 0 2

6r1/3K4/8/8/8/3k3Q/r7/8 b - - 0 2

2K3Q1/8/7k/2r5/b7/8/8/8 w - - 0 2

1nK1Q3/8/8/8/8/4k3/1r6/8 b - - 0 2

how does fen work

Not sure?  When I load a position into WinBoard it allows me to save it as a fen string when I hit copy position.

However, I have no idea how to read it or write it by hand.

Immortalgamer, nebojsa, et al:   to read FEN, you must use algebraic notation.

To start with, lower case is black, upper case is white, blank squares (empty) are numbers, and you start the next 'rank' with a /

chess boards are easiest for beginners if white is always on the bottom edge, heading north - simply for standardization on thinking about it - and which way the pawns are going.   In tactics trainer, it appears that all FEN strings I have seen are set that way.  The board always appears with white on the bottom, heading north due to my settings and personal preference to see it in standard format.

to help you visualize this, see tactic http://www.chess.com/tactics/server.html?id=43947

the FEN string is:

"rnb1k1nr/p5p1/2p2q2/3P1P1p/4Q3/1B6/Pb1N1PPP/RNB1K2R b KQkq -"

thus on a8 is a black rook, on b8 is a black knight, on c8 is a black bishop, d8 is empty, e8 has a black king, f8 is empty, g8 has a knight, h8 has a rook.  the / means return and start on a7.  a7 has a black pawn, 5 means b7, c7, d7, e7, f7 are all empty, black pawn on g7 and 1 means h7 is empty.  the / means return to a6 and start over.  when you encounter CAPITAL LETTERS you place white pieces or pawns as listed.   I have not figured out what the KQkq means at the end of the string, but the lower case b following the capital R at the end means black moves first.  In this example, though, you are playing white and it is white to win.  black threatens a white rook on a1, but being that he is in check, chooses to respond to the check and block with his queen.  Since white's queen is guarded by his knight, and black's queen is now pinned to her king, white simply takes the black bishop on b2.

my apology if that lengthy response is overly detailed.  likely you caught on instantly.