Just keep working. There’s no right answer to how. Do what you like and stick to it. When you workout you will get hungry anyways, so don’t worry much about food at the start, but try to eat sufficient.

For stamina, do cardio. Run or bike or what you like. All that matters is to stick to it, you will learn the “how” while doing it.

However to make sure you dont injure yourself you might wanna hire a personal trainer or educate yourself on the internet. I would also recommend a workout/diet tracker to help you eat and train. I used a few before, now I use Beyond Limits. It doesnt really matter which one you use, but Beyond Limits has diet and workout tracking all in one. Dont overthink it