The (k1, yo, k1) in the next st is a double increase, 3 sts from one. It's shown in this video
but basically the idea is to knit 1, yo, knit 1 into the same st before you drop it off the left needle.
The 4-st RC and the C4F are cable instructions. C4F means put 2sts on a cable needle and hold in front, knit the next 2sts, then knit the 2sts from the cable needle. 4-st RC is also a cable with the first 2sts held in back, work 2sts and then work the sts from the cable needle. These sts might be combinations of knit and purl sts, depending on the pattern instructions. The cable terms should be defined before the pattern begins or perhaps they're located in a side bar or a glossary in a book or magazine.