Both players together must create a third stone. One player has a board with a table (screen below), on which you need to create a stone, and entries around which the components are shown and named.
On the table, these components are indicated as abbreviations.
These abbreviations must be decrypted by the second player, since he has a book with decryptions. Also in the room of the second player there are components with images. And three devices.
One combines two components into one, the second disconnects one component into two, and the third is needed to connect the 3 components that are indicated below the stone in the table (OH, OT, PF).