How will we know that Jesus has arrived as there will be many who will come in the name of Jesus?

Jesus makes it clear in Matthew 24:27-31 that his coming will be obvious to everyone:

For as the lightning comes from the east and shines as far as the west, so will be the coming of the Son of Man… The sun will be darkened, and the moon will not give her light, and the stars will fall from heaven, and the powers of the heavens will be shaken. Then will appear in heaven the sign of the Son of Man, and then all the tribes of the earth will mourn, and they will see the Son of Man coming on the clouds of heaven with power and great glory. And he will send out his angels with a loud trumpet call, and they will gather his elect from the four winds, from one end of heaven to the other.

In verse 43 of the same chapter Jesus likens his coming to that of a thief in the night — this does not mean he will come secretly, but unexpectedly. So there will be no mistake — you will know when Jesus has arrived.

Also see: ‘Where does it say that the Son of Man will come at an hour you do not expect?‘