Jesus's bold claims led to some believing and others rejecting. Of the rejecters, some of them wanted to capture Jesus! Among the people who wanted to capture Jesus are the Pharisees and chief priests, who are the religious leaders of the day.
In response to the Pharisees, Jesus proclaimed that he would be with them for a bit longer before returning to Jesus's sender (Father). In fact, Jesus proclaimed that the Pharisees would seek Jesus but would be unable to find Jesus, and the Pharisees can not go to where Jesus is (AKA the place where the Father is). The Judeans have a bunch of questions on what Jesus meant, with one theory being that Jesus would teach the Greeks.
Based on the context on how the Pharisees wanted to capture Jesus, it's possible that Jesus was referring to physical seeking of Jesus to capture him and throw him down. It's also likely that Jesus talks about how the Judeans would fail to find Jesus (in particular, his dead body) after the resurrection and ascension. Furthermore, Tom Constable talked about how the Judeans would try to find a Messiah when Jesus was the Messiah the entire time (Study Light). Either way, Jesus's time is temporary, and he wants people who are with him in person to learn who Jesus is as well as his credentials while Jesus is still with him.