Got it. The one thing I can't understand in your puzzle is why there is the number '5' in the brackets? I thought it might have hint that we should use only 5 first letters in the word 'alphabet'. Now I don't have clues on how to explain it. :-?No. As Ray suggested, it's (from) H to O. H to O sounds like H20, which is the chemical formula for water.
I've no idea what it could be, frankly. 13 minutes? :-DThis one should now be simple: A B C D E F G H I J K L M, minute (4).