You assume you already understand what the Holy Name is — and you hold on to that understanding as if it were solid ground. Gurudev stops you right there: if you truly understood the subject, you would not be making nāma-aparādha. So the task is not to add one more idea on top, but to erase what is already there. Picture a chalkboard covered edge to edge with writing: you don't need to read it line by line and rub it out — one pass of the cloth, and it is blank again, ready for the first line. Let go the same way of everything you were sure you knew about the Name, and sit down with your beads again, as if chanting the first syllable of your life.