I ran across this BING picture which shows clearly how to start a knitting project with a ” provisional cast on”. That is a cast on that leaves “open” stitches when the contrast coloured chain is pulled out.
I often use it as a permenant cast on and continue knitting. For a bit more weighting on the edge, use the yarn double or triple thickness on the crochet chain.
It can also be used on a knitting machine by hanging the “bumps” onto the knitting machine needles.
I apologize, in that I am unable to give credit to the original photographer.