algebra precalculus - solving this multi-step equation

Alright, so I'm confused.
I have $\frac{1}{2}x + 2 = 4$. To solve it, I multiplied the right side by two and got $x + 4 = 4$, however, that would give me $0$ as my answer. When I subtract the two first, I get $4$ as my answer.

Do I have to do the same to all sides of the equation or only one? So do I multiply everything by $2$ to get $x + 4 = 8$?