Rock hard ice bumps, that's New England for you. Learning bumps from scratch on these things can be done, but remember that most people posting about learning bumps on this forum assume you are learning on soft snow bumps.
First you need to learn to do pivot slips on beginner-intermediate terrain with hard snow. A pivot slip is series of linked side-slips straight down the slope. Your skis don't travel left or right at all. That's the hard part.
Face the bottom of the slope with your upper body, shoulders, hips, arms all facing straight downhill. Keep it that way. Swivel your skis left (they must stay parallel) and slide down a bit, then swivel your skis right and slide down, then left, then right. Your goal is smooth travel, no stopping, no pausing, no turning your upper body, no traveling leftie-rightie at all, just a smooth travel straight down the hill with those skis point all the way to the left then all the way to the right. It's difficult, but well worth the effort. Once your body figures out how to do this you will be ready for those icy bumps.
Search pivot slips here on Epic; there's a great video loop showing a guy doing it for Rocky Mountain PSIA.
Once you can do pivot slips well on a beginner slope, take it to the easiest icy bump field you can find. Your goal is to pivot-slip your way down the field, up and over a sequential line of bumps. Start on top of a bump. Swivel your skis left, slip down into the rut, swivel them right and slip up the next bump. Pause, admire what you just did. Now do it again, down and up, all the way down the line of bumps. Seek to not travel left or right, but just go up and over the bumps, pivot slipping all the way. This process will keep your speed way down.
Do not try to ski a line that flows through the ruts left and right. That's a sure fail on ice.
Do the same run over and over, just like you did when you were learning pivot slips. Seek speed as your confidence and accuracy increases. You'll naturally figure out how to begin traveling a little left-right through the field as you get some mileage doing this.
Once you can get up the speed, you can take it to uglier bumps. Just go slow at first.
I speak from New England experience; this works. I learned on ice bumps.