I must say that the other guides are incredibly confusing in the ways they describe to get the achievement. I thought that I would make a detailed guide to tell you all the ins and out of this achievement.
I have broken the journey towards this achievement into steps:
1. Buy the game 'Minecraft' from the marketplace for 1600 Microsoft points.
2. Start up the game by heading to my games then pressing A on Minecraft to launch it.
3. Start the tutorial world.
4. Walk over to your nearest tree (trees are easily recognised by their brown trunk and green leaves).
5. Move the right analogue stick so that you are looking directly at the tree's trunk.
6. Use your finger to pull down on the trigger at the back right of your controller. This step is tricky, as there is a chance that your finger may slip off the trigger. If this happens you will not get the achievement.
7. After a short while, a block will 'pop' out of the tree, and your achievement will 'pop'
8. Celebrate with expensive champagne and a bag of cheese and onion crisps.