In this example we are multiplying two binomials so FOIL method can be used.
$$ \begin{aligned} \left( \color{blue}{ 2x+3}\right) \cdot \left( \color{orangered}{ x+6}\right) &= \underbrace{ \color{blue}{2x} \cdot \color{orangered}{x} }_{\text{FIRST}} + \underbrace{ \color{blue}{2x} \cdot \color{orangered}{6} }_{\text{OUTER}} + \underbrace{ \color{blue}{3} \cdot \color{orangered}{x} }_{\text{INNER}} + \underbrace{ \color{blue}{3} \cdot \color{orangered}{6} }_{\text{LAST}} = \\ &= 2x^2 + 12x + 3x + 18 = \\ &= 2x^2 + 12x + 3x + 18 = \\ &= 2x^2+15x+18; \end{aligned} $$