This is a simple toe-up ribbed pattern, which I worked as follows:
Using a provisional toe-up cast-on (I like the figure-8 cast-on), cast on 28 sts. I use the magic loop technique on a long circular needle, so this pattern is written for that. The 28 sts are cast on as 14 sts on to each of the front and back needle tips.
Toe round 1: K1, M1, K to 1 st before end of needle 1, M1, K1. Rpt on needle 2.
Toe round 2: K all sts
Rpt these two rounds until you have a total of 56 sts. K 4 rounds even,
Foot: On needle 1, K1, (P2, K2) to last st, K1. On needle 2, K to end.
Rpt foot round until sock reaches the length of the foot to the front of the ankle.
Gusset round 1: On needle 1, work as for foot. On needle 2, K1, M1, K to last st, M1, K1.
Gusset round 2: Work both needles as for foot.
Rpt these two rounds until there are 48 sts on needle 2.
Work once more across needle 1. You will now work back and forth across needle 2 only to turn the heel.
Heel row 1: K27, SSK, K1, turn
Heel row 2: Sl1, P7, P2tog, P1, turn
Heel row 3: Sl1, K to 1 st before gap made by previous turn, SSK across the gap, K1, turn
Heel row 4: Sl1, P to 1 st before gap made by previous turn, P2tog across the gap, P1, turn
Rpt rows 3 and 4 until all sts are used. Return to working in the round.
Leg: On needle 1, work as for foot. On needle 2, work as on needle 1 to repeat the pattern around the leg.
Continue in this pattern as set until leg is required length. Cast off loosely.
(Abbreviations: K - knit; P - purl; M1 - make one; Rpt - repeat; SSK - slip next two sts one by one knitwise, return to left needle and knit together through the back loop; P2tog - purl two together; St/s - stitches)