To create a Flower Pot you will need to find clay; clay can be found underwater near sandy shores or on the ocean floor, it is similar to sand in appearance. Once you have the clay, smelt it in a furnace and it'll turn into a brick. Use three bricks to craft a Flower Plot, place it and the achievement is yours.
Here's a video:
This is a slightly edited version of:
https://www.xboxachievements.com/game/minecraft-xbox-one-edi...All credit goes to the original writer.