It is a steep learning curve at the beginning, it will become old hat. But first keep in mind you are in what we consider the honeymoon period, which means your pancreas might still be making some insulin off and on. The younger you are, usually the shorter period of time that is. But days? weeks? months? A lot of us that get T1 older even years.
It messes with your numbers. The odds are as time goes on you will need more insulin. But they start you out at a lower dose because it's safer until you get a little used to taking insulin plus the fact that your pancreas might still try to help you and make some insulin.
We have to dose for carbs, but sometimes if you are consuming high protein you might have to dose a much smaller amount for protein too And high protein sometimes has a delay in raising blood sugars. Also keep in mind fats can delay absorption of your carbs. It can vary per person. If I eat carbs with a normal or higher protein level for me, I don't have to dose for the protein. But if eat something high protein with low or no carbs, my blood sugars shoot up. Since we can all be so different, it takes knowing how you personally respond. Since you want to be a body builder I suggest keeping a log of what time you ate, Carbs, Fats, Protein intake and when and how much you dosed and then test your blood sugars at the 2 hour mark, 3 and 4 hours. You might be able to get a better idea of your dosing needs. But I would also suggest eat a normal amount of protein with the same carbs and dose and do the same thing so you can do a comparison. And do that a few times.
Insulins highest activity usually is between 1-2 hours, but it still works up to 5 maybe even 6 hours. Be very careful of stacking. That's the sure fire way to cause a hypo. You could try a basal test, but you are so new it would probably change by next week. Right now it's more about learning the dose you need for now and the timing. Do some comparisons so you can try to figure out what effect the high protein is doing. It could be if you spike later without high protein , your basal is off or your I/C ratio is off.
Walking, running, biking usually lowers blood sugars. Hard exercise can raise your blood sugars but less likely if you are used to the exercise. Exercise can be a trick all in itself.
Always carry a quick hypo fix with you at all times, jelly babies or glucose tablets, something like that. Handy within easy reach. By the bedside at night is a good idea too. This is important with your exercise routine especially and exercise can also cause better insulin absorption into the night and the next day.
Be patient, I know you want to know how to everything right away so you can solve it. But our bodies aren't instantly changed overnight. Unfortunately you are so new, the numbers that work for now are likely to change. So you can only do the best you can and try to figure out what amounts you need. If you are in the UK , they have a daphne course to help you learn.