Meaning

1m - 1H;   1m - 1S;
2H - 2S;     2S - 2N;

Bidding 2S/N, the next rank above agreed on major asks opener to make a step response describing trump suit length and overall hand strength

1C - 1H;    1C - 1S;
2H - 2S;    2S - 2N;
2N -     ;    3C -      ;

1st step = 3 trump, minimum hand (11-13 points)

1C - 1H;    1C - 1S;
2H - 2S;    2S - 2N;
3C -     ;    3D -      ;

2nd step = 3 trump, maximum hand (14-15 points)

1C - 1H;    1C - 1S;
2H - 2S;    2S - 2N;
3D -     ;    3H -      ;

3rd step = 4 trump, minimum hand (11-13 points)

1C - 1H;    1C - 1S;
2H - 2S;    2S - 2N;
3H -     ;    3S -      ;

4th step = 4 trump, maximum hand (14-15 points)