asalvo TRIO ROMA II Manuel D'instructions page 42

Car seat can be installed on stroller's frame by adaptors. Position each
of adaptors to the corresponding opening and fix to the car seat with
light pressure, until you hear a click and adaptors are stable.
To remove the adaptors, press buttons from both sides of car seat and
pull each of the adaptors out.
42
INSTALLING OF THE CAR SEAT ON THE STROLLER FRAME
ATTENTION! ALWAYS INSTALL THE CAR SEAT IN A FACE TO FACE MODE
To install the car seat on stroller's frame, insert the adaptors, pull both
levers, located inside the frame, in direction. Position it in a face to face
mode, align the car seat adaptors with the corresponding levers on the
frame and press down until you hear a click and car seat is fixed.
ADAPTORS FOR CAR SEAT