Winterizing Question

[JDHarrin]

First year RVers here. I've read and heard others talk about winterizing their plumbing system. People talk about blowing out their plumbing lines and then adding anti-freeze. My task this weekend is to winterize the rig and install the cover before our first cold spell or snow. I opened the manual to get the procedures for doing so, and it says either blow out the lines OR add anti-freeze to the lines. I thought both processes were needed? Which method is easier and more importantly, which protects the water lines more efficiently...