@dmatos - Rachio mentions if one is using a pump start relay to activate a pump, which is done via a connection to the master valve terminal (M), to place the relay 15 feet away. For a regular master valve there is no relay and no distance restriction.
Just follow @gaustin 's directions. As there are multiple C terminals on the Rachio one can place one wire in each one, no need to double up the wires into one terminal. If one wants to use only one C terminal, then I’d recommend wire nutting in a third short pigtail to the two white wires and connect the pig tail to the C terminal.
And no reason to connect the unused wires on the far right of the box - just leave them disconnected in the Rachio too.
Welcome to the community and enjoy Rachio.