A TDEE calculator is a very simple way to understand what your mantainance calorie intake should be, this in particular is supposed to be quite precise because it makes an average of the two most used formulas to obtain your basal consumption, the Harris-Benedict and Mifflin-St Jeor equations.
Also learn how to split your macros in the bodybuilding guide for beginners and how to optimise your caloric intake periodisation during the week by implementing carb cycling in your nutrition plan.