What is the first step in most stoichiometry problems?

Explanation:

Stoichiometry is the cuantitative study of the chemical reactions.

It is like algebra applied to chemical equations.

The cuantitative relations between the amount of reactants and products is determined by the law of conservation of mass: the number of each kind of atoms in the reactants must equal the number of the same kind of atoms in the products.

Once that relation has been established, as mole ratios, then it can be determined the amount of reactant neeed to obtain a certain amount of product, or vice versa, determine the amount of product that can be obtained from a given amount of reactants.

That is why, after you know the reactants and products in a chemical equation you must balance to assure that the relative amounts are properly established.

answer is: nuclear fusion produces elements that are heavier than helium.

nuclei combine to form a heavier nucleus, releasing energy.  

for example, fusion of hydrogen atoms at the sun.  

this fusion nuclear reaction is in the inner core of the sun and hydrogen (atomic number 1) is conveted into helium (atomic number 2).  

the inner core is the central region of the sun and all solar energy is produced in the core by nuclear fusion.