RES pin on the CP20102 is completely useless, should have never been brought out to a pad at all (it resets the CP2012 - there is no need to ever do that).
DTR pin goes to GRN pin on the Pro Mini. TX and RX may need to be swapped over as they go from one board to the other - or may not! Theoretically, the pins on the CP2102 board should plug directly to the corresponding Pro Mini pins in the same order.
Ground must be connected of course.
Do all that and you will be good to go!