If you miss this achievement in career mode you can later replay all locations and co in Free play mode and get your missed achievements there.
There are 12 lanterns in the Treehouse.
To make the achievement extremely easy, go to the job overview, find the lanterns and select them, after that the lanterns are highlighted in the game.- Lantern 1 and 2 are at the beginning of the stairs to lower deck
- Lantern 3 is at the middle deck on a tree
- Lantern 4-11 are hang on the side of the house all around
- Lantern 12 is at the beginning of the spiral staircase (below)