This is what I posted from my experience in another post, may help you. The thing to remember is its a marathon not a sprint, it has to be a sustainable change in diet and exercise otherwise you will very quickly pile on the pounds again.
"I was in the same boat as you around 2 months ago. I had excess belly fat which really started to annoy me and wanted to lose fat. Over the past 6 weeks I've lost ~4-5kg and it took a bit of trial and error with insulin and diet.
First tings first, you must get your blood glucose levels under control, too low glucose and you will eat unnecessary calories, too high and this is not only of detriment in the long term but increases muscle breakdown - which is essential for fat loss (as more muscle uses more energy essentially).
I have been doing a mix of HIIT and weight training, generally the HIIT lasts 20-25 min max and weight training I typically focus on one area such as back/chest/legs. everyone does it differently, but because my main aim was fat loss I start with cardio and then follow with weight training, I then cool down with 5-6 minutes on the bike.
One thing I noticed was my glucose levels dropping during training due to HIIT, so either take a bottle of lucozade sport with you or ensure your glucose levels are slightly elevated before going to the gym, secondly I dropped my basal insulin from 26 units to 20-22, as I typically go to the gym after work to prevent hypos during the night.
Also important as stated before is your diet, I still ate what I did before but I reduced my portion sizes, also remember you will likely require less insulin following training, if you inject too much you fall back into the cycle of hypo and extra calories.
Stick to a rather simple diet so you can become aware of how much insulin is required.
I learned a lot from the Diabetic Muscle and Fitness website and YouTube channel, so that's also a good source of info.
Hope this helps."