Build a vertical shaft for the elevator
Place blocks for the elevator frame
Choose the elevator type you want
For a water elevator, place soul sand at the bottom for upward movement
For a water elevator, place magma blocks at the bottom for downward movement
Fill the shaft with water source blocks
Use kelp to turn flowing water into source blocks
Add signs or trapdoors to keep water contained
For a piston elevator, place sticky pistons in the desired layout
Add slime blocks or honey blocks to move the platform
Connect pistons to redstone
Add buttons, levers, or pressure plates for activation
Test the elevator
Adjust the redstone timing if needed
Add floors and exits at each level