@McTag,
John is juggling many things and walks into a lift , and then the person already inside says 'Which floor?', and then John says, 'second floor, please.'
1. Is the conversation natural English?
2. Or if the person doesn't ask John, can John say these?:
-Can you help me punch 'second floor'?
-Can you help me by punching 'second floor'?
BY is difficult here. When you help me do my homework, we almost do it together; When you help me BY doing my homework, you do it alone. Is it right?