Hi, I am still confused about "go to bed". We can say "I will go to bed at 10 pm". But what if I am already on the bed, shall I say "I will go to sleep at 10 pm" instead?
If I was sitting/lying on the bed, or even in bed reading, for example, I'd say 'It's 10 o'clock now; I'm going to sleep' (though this doesn't happen instantly).
You cannot choose the exact time you will fall asleep (short of giving yourself a general anaesthetic).