Lot’s of good suggestions here. I found the book, “Think Like a Pancreas” very helpful. It’s a LOT of information and I had to sort of pick and chose what seemed important at that time, and I still go back and reference it at times. The MOST important thing I learned was the TIMING of the bolus. The author has a chart which includes the glycemic index of the food and your starting BS range. I reference that chart quite a bit.
I also found that after having diabetes for about a year (I’m at about 18 months post diagnosis) things calmed down a bit in terms of spikes. I still spike at times, but much less. I think part of the early difficulty is your body is adjusting the something new injected into it (synthetic insulin) and learning how to respond.
Lastly, I can’t stress how much hormones play a role. At different times in my cycle I run high and low, and am more reactive to carbs.
Hope this helps. Give yourself time to get used to all this, and forgive yourself when you make a mistake.