Apart from books, your most important source of information will be recordings. Listen to albums which feature piano or keyboard players. Since the roots of Rock go back to earlier Blues and Boogie piano playing, it is important to listen to players in those styles as well as more recent Rock players.
Some players to look out for are Otis Spann, Memphis Slim, Dr John, James Booker, Professor Longhair, Ray Charles, Aretha Franklin, Herbie Hancock, Art Neville, Richard Tee, Bernie Worrell, Stevie Wonder, George Duke, Billy Powell, Donald Fagen, Leon Russell, Jackson Browne, Benmont Tench, Elton John, Billy Joel, Bruce Hornsby, Jon Lord, Keith Emerson and Ben Folds.
When you are listening to albums, try to sing along with the solos and rhythm parts, and imagine the fingerings and techniques you would use to achieve the sounds you are hearing. This helps you to absorb the music and before long, it starts to come out in your own playing. It is also valuable to play along with albums, sometimes imitating what you are hearing and other times improvising. This is very good ear training and is also a lot of fun.