Hello. I'm working on the Head First Java BeatBox project and I'm really confused on the part where they have the two for loops. I'm not sure what is supposed to go in the checkboxList.get() method. How does it work? They have it as checkboxList.get(j+(16*i)); but if it goes from 1 to 256 shouldn't it be i*j? Also I'm confused about where I can get more information about Java's libraries and classes like MIDI sound. For example, where would I find out information like 35 represents the Bass Drum sound in MIDI sound? I looked in the API documentation but they seem to have limited information. Can you tell me what you use to find detailed information about how certain Java libraries and classes work when you are doing projects? Can you give me a link? Thank you.