If you just want some hints to help you figure it out, then read the posts above and maybe play back through the game again. If you want to be told explicitly how to unlock "The garden in the temple.", then uncover the following spoiler:

- Unlock the Achievement "Clear night in Uyuni" by finding the blue coral in Pre-Conscious - Tearless Lake and solving the associated puzzle.
- Unlock the Achievement "Mind: Path to Amsterdam" by finding the mushrooms in Conscious - Wood's End and solving the associated puzzle.
- Unlock the Achievement "Antelope" by entering the left elevator in Trauma - The Lone Hospital and solving the associated puzzle.

Locate the three pieces of furniture:
- The bed is in Unconscious - Light In The Deep, up the tunnel where the red sparking ball came from and finding it unlocks the achievement "Aftermath"
- The desk is in Pre-Conscious - Lost Hills on top of the next-to-last hill (and presently has no achievement associated with it)
- The closet is in Conscious - Wooded Cliff on the edge of one of the wooded islands and finding it unclocks the achievement "Aftermath II"

Once you have completed the above tasks, return to Unconscious - Dark Void and progress until you reach the glowing red fissure portal. Enter it to visit the temple. If you've done everything correctly, the zen garden in the center will now be a glowing portal. Enter it to unlock "The garden in the temple."

(Strangely, it seems that a larger percentage of players have unlocked "The garden in the temple." than have unlocked Clear Night and Path to Amsterdam, but this may be a result of pre-update achievements carrying over.)

Originally posted by ReverendTed:

- The desk is in Pre-Conscious - Lost Hills on top of the next-to-last hill (and presently has no achievement associated with it)

oh my, I must be blind..
because it's impossible to miss, you have to pass next to it in order to proceed to the next level...

thank you :)

Originally posted by ReverendTed:

Once you have completed the above tasks, return to Unconscious - Dark Void and progress until you reach the glowing red fissure portal. Enter it to visit the temple. If you've done everything correctly, the zen garden in the center will now be a glowing portal. Enter it to unlock "The garden in the temple."

Where exactly do you progress to find this glowing red fissure portal? This is the stage where you can't move and just look at white particles, right? Maybe I have done something wrong, but do you need to do any of these objectives in one playthrough? I just went back and did all the puzzles except Antelope in one playthrough.

Is there a puzzle in the Lone Hospital area after you activate the portal in the left elevator? The game pretty much always forces me to fall when I enter or forces me to the title.

Oh, is there a difference between the Enhanced Edition and the one before for this achievement?

Originally posted by ReverendTed:

(Strangely, it seems that a larger percentage of players have unlocked "The garden in the temple." than have unlocked Clear Night and Path to Amsterdam, but this may be a result of pre-update achievements carrying over.)

It is possible to get the achievement for "garden in the temple" by playing the "old_mind" beta of Path to Thalamus (the old version to be precise). In this version, you don't need those three preliminary tasks to achieve "garden in the temple".

Do you recall what you need to do for the achievement in the Enhanced Edition? Visiting Dark Void just sends me to an Epilogue.

After watching a video, I remembered where you likely have to go.. I guess start a new game until you get to the point you get to follow to the red mentioned portal from earlier..

There's an error with the menu we need to solve. You can play the prologue and the next one is the dark void.

Sorry for the inconveniences.

Originally posted by ReverendTed:

....

Thank you!