to start, make 4 markers (or perhaps 8!)
label them Needle 1, Needle 2, etc-- (or just 1, 2, 3, 4)
cast on (toe up/cuff down) and place markers on stitches/needle to note where the stitches for needle 1 are , same for other needles.
(you can have all the stitches on 1 needle (magic loop style, and still 'label' some stitches as needle1 needle2 , etc)
then just follow directions!
you can keep track of 'where you are' and follow pattern, and work with any number of needles! 1, 2, 4, 5!
you can make paper markers or buy those 'baby braclet beads' --they also come in numbers as well as letters) to make numbered stitch markers (or you can buy them ready made
or you can just use unnumbered markers to define the stitches of needle 1, 2, etc!