Make a foundation row or round in your chosen stitch
Yarn over, insert hook into the stitch, yarn over, pull up a loop
Yarn over, pull through 2 loops on the hook
Repeat the previous two steps in the same stitch until you have multiple unfinished double crochets on the hook
Yarn over, pull through all loops on the hook
Chain 1 to secure the bobble if needed
Work the next stitch according to your pattern
Repeat in the specified stitches to create more bobbles