P.S. In response to the comment in your "thank you"...
You need "step by step" help with doing what? All you have posted is an equation. What have you been asked to do with the equation? The problem is more than just an equation. There should be some kind of instructions to go along with the equation. For example, "Simplify" or "Find the value of y to the nearest 1000th" or "Rewrite using fractional exponents".
P.P.S. If you repost your question with the instructions included, please put the radicand (the expression inside the radical is called a radicand) in parentheses. If your equation is
then post it as
y = 16.3sqrt(4+23)
If your equation is
then post it as
y = 16.3sqrt(4)+23