How do I replace this smart switch to this exisiting light switch
what seem to have installed is a manual dimmer then one end of a 2-way switching setup,  the cable with red and white carries the selection made at this switch to the other light switch. or possibly it receives the selection from the other switch.

The three terminals on that switch have embossed labels, but the colour rings carry the same message.

black is neutral
red is active 
white is the output to the lamp.

as for wiring this end those two blacks go in the black hole (labeled N for neutral)
the red from the 3-wire cable goes to red (labeled A for active) and the red from the red-white cable goes to white. (labeled A1) use the joiner taken from the neutral wires to join cap the end of the white wire.

At the other end  the red-white wires will go to a switch and there'll be another red witre, join those two red wires and put another cap on the white wire. fit a blind face plate attache the remote control.

once you figure out when end of that setup the power comes in from that goes to the red,  switch the switch on and off, the wire that stays live all the time is the input, it goes to red.

the one that goes live when the light is on that goes to white.

the other one gets a cap, and the two neutrals can go in the black hole.

the other switches for this light on this circuit will have to be disabled that means removing them and joining the wires permanently.

or maybe you should get a smart switch that has a wired remote.