The dashed lines represent rays of infra-red light, which are broken every time someone walks through them.
The letters in the squares are directions. e.g. 2S means you must go two squares south from here.
A compass is included.
N
E
S
W
1E
2S
1S
2W
4W
2S
1E
2S
1N
1E
1E
1S
2N
1W
1S
1S
1W
2N
1W
4W
3E
1E
4N
1N