Alchemy Class Artifact?

[Mors17]

I'm probably missing something very obvious, but I can't figure out where to find the alchemy class artifact to place at the temple to finish the prison map checklist.
I found the prison artifact and placed it, but the alchemy class map did not unlock so I guess there is a second artifact somewhere that is needed?

[x!thyl]

You have to collect the 4 pieces of the plate next the door on the 2nd floor. For this you have to use the boards on the ground to build stairs.
Building the stairs can be a bit tricky, just try to put them, where you would assume a stairway would be (at the back wall on the right corner) and when the first on snaps into the correct place, the others should be easy.
In the room behind the door, the artifact should be on the table.

[Mors17]

Thanks, but that is in the alchemy class map.
What I had missed was that there is a prompt to press use on the hand for the alchemy class artifact. I did not connect that the find the prison artifact and place alchemy class artifact objectives were meant to be for the same artifact.