k: knit | p: purl
R: row | Rnd: round | st(s): stitch(es)
RS/WS: right-side facing/wrong-side facing
pm/slm: place marker/slip marker
yo: yarn over, starting at front of work pass yarn over needle to back. When you reach a yo on next row, k as directed. This should create a hole.
ssk: slip next st k-wise, slip following st k-wise, insert tip of left-hand needle into these 2sts (right to left) and k together as one.
sl: slip a st without working from left to right needle
k2tog/p2tog: k/p 2sts together as one st.