The pattern is telling you to put those stitches on waste yarn as you will need to go back to them and use them later in the instructions. Rather than using waste yarn, you can put those stitches on a stitch holder.
You break the yarn before putting the 16 stitches on a holder (when you break the yarn, leave a tail of a few inches as you don’t want to have your knitting unravel), then once the 16 stitches are on the holder, rejoin the yarn after those 16 stitches, work the 74 stitches, then break yarn again etc as in the instructions.
Sorry if I’ve confused you further…