What does c4f and c4b mean in my pattern?
That is cable 4 front and cable 4 back. Your pattern should have an explanation how to do them between the gauge info and cast on instructions. Should be something like this -
c4f - slip 2 sts to cable needle, hold to front, k2 from L needle, then knit the sts on the cn.
c4b - slip 2sts to cable needle, hold to back, k2 from L needle, knit the sts on the cn.