The introduction states:
Solutions to clues are entered cyclically in their respective rows and columns. For example, if 8 across started in column 4, it would proceed across to the right hand side for the first eight letters and then continue from the left hand side of the same row for the last seven letters. Solvers must insert the solutions where they will fit together using this method throughout. It may help to know that no entry starts at its numbered square. When complete, solvers must discover the hidden NINA within.