Step 1: Write second polynomial below the first one. Making sure like terms are lined up.
$$ \begin{array}{lrrr} & 2x^3 & -2x & -3 \\ \color{blue}{ + } & & 2x & 5 \\ \hline \end{array} $$Step 2: Combine like terms (add each column):
$$ \begin{array}{lrrr} & 2x^3 & -2x & -3 \\ \color{blue}{ + } & & 2x & 5 \\ \hline & 2x^3 & & 2 \end{array} $$