Hey matthew. Let me give this a shot.
Building muscle and shredding the bodyfat at the same time is possible but not easy. The two things are almost eachother opposites so going for both is a matter of discipline.
The first thing you need to realise this whole procces is alot more about eating than training.
In this process losing the fat will take longer. Because you cant eat too much beneat your daily need ( otherwise no muscle gains ). And the muscle gains will come slower than while bulking(eating above daily need).
This is pretty much the basic information about this process.
The main parts are weighttraining and eating. Cardio wont be the biggest factor in my opinion. But a good thing next to those 2.
Will come back on those 2 later.
Hi... you are male
Pfft... damn phone. Anyway you are male and likely younger than me but here is what I have learned through studying nutrition and biology. Protein. Protein. Protein ... a diet over the recommended grams in protein allows our muscle to absorb protein at a cellular level. Its a complicated process but protein cells are a bit cannibalistic and prefer to eat muscle than fat cells. So if our diets are low in protein all the work we do to build muscle and get rid of fat is actually detrimental because our muscle is ends up depleted. I hope it makes sense. Trudy
That you are 13 kind of changes the whole idea hehe. If i where you u should do mainly bodyweight training and next to this just eat what you like. Next to this try to add some extra protein to your diet.
Your welcome. I wish someone would have told me that at your age :-)