How do you find the slope and y-intercept for the line y=1/2x+6?

The slope is $\frac{1}{2}$ and the $y$-intercept is $6$.
You can actually plug this equation into a graphing calculator and you will find that each $y$ value will be $\frac{1}{2}$ the $x$ value plus $6$.
The $y$-intercept simply means the value of $y$ when $x = 0$.