In order to unlock this cheevo, you will need a enchanting table and a decent amount of exp, Lapis-Lazuli, a Grindstone and kill The Drowned Zombies.
To craft a enchanting table, you will need:
- 4 Obsidian
- 2 Diamonds
- 1 Book
Now that you will have an enchanting table, go to oceans/lakes and kill the drowned zombies until they drop a Trident.
To enchant something in the Enchanting Table, you will need to find Lapis-Lazuli. Lapis-Lazuli ores are found while mining, commonly found at Y 13-16. (But is found at Y 30 and below.) then melt them in a furnace.
Now insert the Trident and Lapis-Lazuli on the enchanting table. The table will give you 3 sets of enchantments. If you don't see Riptide, keep enchanting 1 exp enchantments until it appears. You will need to grind for exp if you run out of exp. So kill monsters and melt ores.
To remove the 1exp enchantments from a Trident, you can use a Grindstone.
To craft a Grindstone, you will need:
- 2 sticks
- 1 stone slab
- 2 types of any planks.
Once you are with a Riptide enchanted trident, go on water and press/hold
. After a few seconds the acheivement should pop up.
TL;DR: Get a Trident from the drowned, get an enchanting table and Lapis Lazuli, enchant 1 exp enchantments until you see Riptide, go on water and press/hold LT.