The turning heel consists of short rows to shape the curve around the heel. The stitches in the middle are knitted, with paired decreases fanning out from the center, as the outer stitches are brought into the pattern. The travelling, paired decreases form a triangle which fits around your heel and the outer stitches form the curve. This section knits up very quickly.
The term short row, is a row in which you do not knit completely across. For the heel, it is bordered with slip stitches on either end, whose function is to visually blend stitches to form a smooth transition with the regular stitches on the ends of the row.
The basic sock pattern uses a French heel--a slip-stitch, honeycomb pattern that provides comfort, fit and durability. For the heel flap, you will be working with only 30 stitches and a 2.0 mm circular needle. The stitches are worked back and forth on the single needle for a total of 30 rows. A chain stitch selvage makes it easy to later see and pick up stitches for the gusset.
The tools that I use for projects are listed here. Knitting and crochet needles have their own separate blog entries. I will add to this basic list, as I reference tools in projects.
Stitch Markers: I use two types of split ring markers, one type (white in the photo) that I really like but haven't been able to find anymore. The small white, split-ring markers are very useful when knitting and marking fingering and sport weight yarns and when using small diameter needles. The green and orange markers locking stitch markers are better for larger diameter needles, when you want to hold a few stitches at a end of the row for completion later, to temporarily hold a dropped a stitch, or for marking increases and decreases. The green and orange markers are Clover Locking Stitch Markers (#353).
My knitting needles range in diameter from 1.2 mm to 12.0 mm, comprising straight needles (Aero, Redditch England) from 2.25 mm through 8 mm, double-pointed needles, DPNs (Aero, Knit Picks and Susan Bates), from 1.5 mm through 7.0 mm and circular needles from 1.2 mm up to size 8.0 mm (Knit Picks and HiyaHiya). (See related article, "My Needle Choices," if you are interested in how I select needles for specific tasks.)
From size 6.00 mm and larger, the Aero straight needles are made of stiff plastic. Most of my circular needles are nickel-plated from Knit Picks (fixed circular for the smaller diameters and interchangeable needle tips for the larger sizes). My very small, stainless steel circular needles (<= 1.75 mm) are from HiyaHiya. I use small, anodized aluminum DPNs (1.5 mm - 2.25 mm) from Susan Bates. These are conveniently colored to make it easy to distinguish among the small needles. Other than the small diameter needles, any DPNs I have purchased recently to satisfy a project need are nickel-plated needles from Knit Picks.
I inherited a set of long, straight, plastic needles in sizes up to 6.0 mm (unknown manufacturer) that I find too flexible (hence too slow) for most knitting purposes, other than for casting on or for holding stitches. These are not included in the attached cross-reference table.