The Hunt is on
To trap a Guardian, the first thing youll need to do is find one. Look in the uppermost rooms of ocean monuments, but be careful. Theyre tough foes.
Then youll need to lure it to the overworld. Build walls between the monument and the surface so it cant escape, and have some railways to hand.
Before you bring the beast home, it needs a place to live. Design a tank thats at least 3x3x3, fill it with water source blocks, and build a railway to it.
This bit is tricky, so be patient. Extend your railway down inside the walls, then use water streams to get the Elder Guardian into a minecart.
Do the locomotion
Either push the Guardian back to your base yourself or use a furnace minecart. Either way, youll want to use invisibility potions to stay safe.
No place like home
Once your new pet is in place, break the minecart to get it out and seal up the roof. Then step back to admire your handiwork