Tonight at sundown, the Passover meal will be eaten. In the Jewish system, Friday begins at sundown. Thursday morning is thus spent getting ready. A room is readied for Jesus and his disciples.
Some think that Jesus' instructions show he has already prearranged to set up the meeting secretly. Go to such and such a place and you'll see a man with a jar. He'll give you further instructions.
The words that Jesus uttered over supper--this is my body; this is my blood--these are mentioned so early. Paul mentions them in the early 50's and claims the words come from Jesus. Since eyewitnesses were around to disagree, it is hard to imagine that Jesus didn't actually say these things.
So Jesus knows he is about to die.