Sometime around this time of year (the exact date is unknowable for several reasons), Jesus of Nazareth rode into Jerusalem on a donkey.
Despite all the controversy he had caused, there was quite a crowd excited by the idea that Jesus would make an appearance in Jerusalem at the Passover. After Jesus had brought Lazarus back to physical life, a lot of people had started believing in him, (11:45) and were spreading the word (12:17).
John gives us several clues that something special was happening: -- the huge crowd acclaiming Jesus (12:12-13), described by the Pharisees as 'the whole world has gone after him' (12:19) and then Jesus saying that by his crucifixion he would 'draw all men' to himself' (12:32). And, the crowd shouted "hosannah", which comes from the Hebrew expression "save us now" used in Psalm 118:25.
So in this 'triumphal entry', we have a small picture of the actual spiritual result of the crucifixion: salvation for all humanity, arriving through a humble King. This wasn't just a parade but an announcement!
And by telling the story, John is inviting us to join this crowd in praising Jesus and looking to him for salvation. Shall we do that together? There's plenty of room!