So here's my own solution, step by step, to help those getting everything they need to unlock this achievement.
It is, in the end, pretty easy to get.
You'll need to craft 3 main things : a loom, the banner, and the banner pattern.
First thing you have to do is creating a new world in survival mode, using the seed prosplank (so you write this exact word). Enable "bonus chest" at start and "show coordinates" as well. Choose the peaceful difficulty mode to make things easier then launch the game.
When you spawn, pick the planks, sticks and tools/weapons (axe or pickaxe) in the chest on your left then turn around (180°). Go straight ahead and exit the forest. You'll reach a river. Cross it and harvest the sugar cane (x2) down the hill. (1617, 63, -43)
Climb the hill to reach the steppe. If you encounter any sheep (mainly white), kill them and pick their wool.
Keep going straight ahead to reach the desert. If you stick to the road, you'll reach a small river with some sugar cane (x2) (1664, 63, -191). Collect it again so you'll have 4. Climb the desert hill and keep going straight ahead.
You'll come across a second river. Cross it again and right in front of you, just before the brown mountain, you'll reach a pyramid with a small building nearby (1634, 69, -410). Get into the small building, go down the stairs and follow the path on your right to reach a lighten room, some meters ahead on the right.
Right in the middle of this room is a purple block (1642, 65, -406). You can dig any of the sand blocks around the purple one but don't dig this last one since there's a detection plank below which triggers TNT blocks.
Jump into the hole you just dig and don't move from the block you're on. You'll find 4 chests around you. Pick every sand blocks you'll find in them and, more important the enchanted apple, the silver ingots (thanks to OhMyGoth1
) and the spider thread.
Use the sand blocks to create a pillar to reach the surface right above you. Exit the structure to come back into the desert.
On the right of the brown mountain, behind the desert temple (the pyramid) is a new steppe. Go to this place and pick yellow flowers.
Now, the hardest part will be to find enough sheeps to get wool blocks for crafting the banner.
Now you need to craft a workshop, using 4x planks, to craft shears by using 2x silver ingots. This will greatly help you to collect wool blocks from sheeps because you can collect up to 2x wool blocks each time you shear a sheep, instead of 1x wool block when you kill one. Once your shears are crafted, you can destroy your workshop and put it back in your inventory to use it later.
Around this place you'll find sheeps. If you only encounter lamas, keep exploring this area. Behind the mountain range is a new forest with meadows to help finding sheeps. You'll see it in the background, on its right.
Once you have 6x wool blocks, set the workshop from your inventory onto the ground.
Then, using 2x planks and 2x spider threads, craft a loom.
Use the yellow flowers to craft some yellow dye.
Next step, use 3x sugar canes to craft paper.
Use 6x wool block and a stick to craft a banner
And, finally, use the enchanted apple and a sheet of paper to craft the banner pattern.
Now, set the loom on the ground then use it to place the banner, a yellow dye and the banner pattern to craft the enchanted apple banner. Once crafted (the model looks like Mojang's logo), put it into the ground and wait a bit until the achievement pops.