they are not working in sections, they are spiral knitting.
try it at home.
take a set 5 dpn's cast on and make some ribbing
then take 3 more balls of yarn
Knit needle 1 with Yarn A (cast on yarn)
knit needle 2 with yarn B (drop yarn A at end of Needle1,)
knit needle 3 with yarn C (drop yarn Bat end of Needle2,)
knit needle 4with yarn D (drop yarn C at end of Needle3,)
you've knit 1 round.
Now you are back to needle 1 (and there is no yarn available to knit with except yarn D (at the end of Needle 4.)
Knit needle 1 with Yarn D
At the end of Needle 1, there are 2 yarn--D that you just used, and A from previous round. Drop Yarn D
knit needle 2 with yarn A
At the end of Needle 2, there are 2 yarn--A that you just used, and B from previous round. (Drop Yarn A)
knit needle 3 with yarn B
At the end of Needle 3, there are 2 yarn--B that you just used, and C from previous round. (Drop Yarn b)
knit needle 4with yarn C
At the end of Needle 4 is NO YARN Except C and you have just completed round 2--
start round 3 with yarn C, (d, a, end wtih B
start round 4 with B (c, d, and end with A)
Round 5 starts with A (it take 4 'rounds for yarn A to work
'round' to being in the starting position!)
(its sound harder than it is..)
you get spirals of color, and no jogs, (and no really 'carries" of yarn either)
continue this way, and you can make a sock out of 4 mini balls of yarn-- (or you could make a tubular scarf, or a hat, or anything knit in the round.
to go a big sock, sub Circular needles for the DPN. (and think about it, circ's are DPN's!)
assign 1 knitter to each Circular needle.
Knit with not a set of 4 DPN's but a set of 8 (circular needles being used as DPN's)
(you can use any number, 4, 5, 6, 7, 8.... but even number are easier (and if you are making an '8 hand shawl' (knit in the round, with 8 increases every other round, 4 or 8 knitters/needles make it easier to keep track of pattern!)
use 8 balls of yarn --1 ball of yarn for each knitter/needle.
i suggested in the 'try it" --each circ has its own ball of yarn, and the yarn moves round and round.
(but since 8 knitters are working at once, as knitter 1 finished stitches on Needle 1, (with yarn A!) Knitter 8 is also finishing stitches on Needle 8 (with yarn H!)
and knitter 1 can start to knit the stitches on her 'needle' with yarn H! It would take 8 round for Yarn A to come back to Knitter 1
this won't make sense if you don't understand the spiral part with 4 DPN's! (which is why i say try it!)
here is an image of socks made with 4 solid colors of yarn
(white/yellow/green/blue) knit spiral. (for a image of finished sock find link on my blog to sock album (page 5 of album!)