Please help alter pattern from flat to circular

[G J]

I haven't found a pattern that has what I want, so I want to adapt one to make my own. I'd like to make a SIMPLE baby sweater in two colors with a cable down the front. I found this pattern but I want to knit in the round as much as possible AND I want to add the cable. SO I'm re-writing the pattern. Can someone help me with the details?

I got the cable part written with help from Jan in CA, Jints, Dakatzmeow and others, but I need some help with changing the pattern to circular. The bottom of the sweater is no problem. It's the sleeve and neck shaping that I'm not sure about.

I've been trying to figure out how to attach the pattern as a word doc, but I can't so here's the pattern with my questions: The yellow highlighted stuff below I have switched to circ, but need to fix it so back and front split at some point for sleeves, neck, etc. I HAVE included the original instructions below as well, which of course, will be deleted, but I thought it would help.
Body: Using CC, CO 98 (110, 126) stitches on the smaller needles. Join, placing stitch marker at join and at 52 sts, to divide back (46 sts) and front (52 sts) and work 10 rows of garter stitch (K row, Purl row ) until it’s (1½ inches [4 cm]).
Change to larger needles and MC. Rows 1-4 and rows 6-7: *K 16, p2, k8, p2 k16, move marker, k to next marker. Cont from *. For 4 rows. Row 5: K 13, p2 hold 4 stitches on cable needle in front, knit 4, knit 4 from cable needle, purl 2, k 13, k back. Continue this 7-row pattern until the f measures 10.5 (11.5, 13.5) inches. [26½ (29, 34) cm] Mark center 20 (22,26) stitches for neck, and end with a wrong side row.
QUESTION: How do I change the shaping for the back and front, shoulders, etc? Below are the original instructions:
Back:
Using CC, cast on 46 (52, 60) stitches on the smaller needles. Work 10 rows of garter stitch (1½ inches [4 cm]). Change to larger needles and MC and work in stocking stitch, starting with a knit row (right side). Continue even until the back measures 10.5 (11.5, 13.5) inches. [26½ (29, 34) cm] Mark center 20 (22,26) stitches for neck, and end with a wrong side row.
Shoulder placket. (Left shoulder) Cast off 33 (37, 43) stitches knitwise. Knit across remaining 13 (15, 17) sts. Purl back 13 (15,17) sts. Knit one row. Purl one row. Turn and cast off knitwise.
Front:
Work as for back until front measures 8¾ (9¼, 10½) inches [22 (23½, 26½) cm] from start (end by working a wrong side row).
Start neck shaping
Work first 18 (21, 25) stitches (left shoulder). Leave remaining stitches on holder. Turn.
Left Shoulder
On neck edge, decrease 1 stitch every row 5(6, 8) times as follows: On wrong side rows P1, P2tog, P to end of row. On right side rows K to last 3 sts, K2tog, K1. 13 (15,17 sts remaining) Work even until the front measures 10 (11, 13) inches [25.5 (28, 33) cm] ending on a wrong side row.
Buttonholes. (left shoulder).
Knit one row, purl one row, then knit 2 (3, 4) make a buttonhole, knit 2, make a buttonhole, kit to end. Purl back. Turn and cast off knit-wise.
Right Shoulder
Pick up stitches from holder. Attach yarn at neck edge. Cast off center 10 stitches (base of neck). Complete this row.
On neck edge decrease 1 stitch every row 5 (6, 8) times as follows: On wrong side rows P to last 3 sts, P2tog through back of loop, P1. On right side rows, K1, K2tog through back of loop, K to end of row. 13 (15, 17) stitches remaining. Work even until the right front measures 10½ (11½, 13½) inches [26.5 (29, 34) cm] ending on a wrong side row. Cast off Knit-wise.
Sleeve. (Make two)
Cast on 24 (26,28) stitches in CC, on smaller needle. Join, placing marker at join, and work 10 rows of garter stitch (1½ inches [4 cm]). Change to larger needles, and MC. Work in stockinette stitch, increasing one stitch at start and end of 1st row. Then increase 1 stitch at each side of marker every 2nd (2nd, 3rd) row 10 (9, 12) times, and increase 1 stitch at each side of marker every 2nd (3rd, 4th) row 0 (2, 1) times. (46 (50, 56) stitches) Work even until sleeve measures 6 (7, 8½) inches [15 (18, 21½) cm] from start.
I’m not sure how to adjust the next parts for working in the round (ML):
Start sleeve cap shaping
On the next two rows cast off 7 (8, 4) stitches. (32 (34, 48) stitches). On the next two rows, cast off 8 (8, 5) stitches. For the largest size only, cast of 5 stitches on the next 2 rows, and cast of 4 stitches on the following two rows. (16 (18,20) stitches remaining) Cast off remaining 16 (18, 20) stitches.
Neckband:
Sew right shoulder.
Use the smaller needle and CC. On neck edge pick up and knit 7 (9, 13) stitches from the shoulder down the neck shaping, 10 stitches from front of neck, 7 (9, 13) stitches from other neck shaping, 20 (22, 26) stitches from the back and 4 stitches from the placket. 48 (54, 66) stitches. Work in CC, and garter stitch for 8 rows, but on row 4, knit 2, make a buttonhole, knit to end. Continue until 8 rows of garter stitch total. Cast off.

Thank you SO MUCH for your help!

EDIT: My highlighting didn't show up. SORRY-I tried. Also, It's turning all the 8 )'s into smilies!

[Ingrid]

If you knit the body up to the armholes in the round, then you can divide the front stitches and back stitches. Put one or the other on a holder or long circ and work the other. At that point, you can pretty much follow the directions as if they were knit flat.