There was no mention of that in the first post!the Ring Video Doorbell Pro I was trying to install
The instructions in that link are not very clear, and are more suited to USA doorbells.
Simply connect one of your bell push wires to one of the transformer terminals.
Connect the other bell push wire to one end of the red wire supplied with the Ring, using the orange and grey connector supplied.
Connect the other end of the red wire to the other transformer terminal.