Noteblocks is a parkour map with seven levels. They vary a bit, but in every level there is a noteblock. If you stand on it, it will teleport you up three blocks. Three more blocks with special abilities are included.
Anvils: They will summon an anvil above you.
Packed Ice: It gives you swiftness.
Spikes (Iron bars): They will kill you when you jump along them or stand on them.
Every level had the same length but it has not the same difficulty.
At the beginning, there is a chest. You must open the chest. Inside, there is a barrier. Put this barrier in your 8th slot. That is the one to the right in your hotbar.