To get to El Quisco from Santiago, you can take a bus at the Santiago bus terminal (located at the Universidad de Santiago metro station) to El Quisco.
The trip takes approximately 2 hours.
It is also possible to arrive by car on the Autopista del Sol in the direction of San Antonio, taking the exit towards El Quisco.
Another option is to take a train from the Alameda de Santiago station to the San Antonio station, and from there take a bus to El Quisco.
See more about how to get to El Quisco