The slope intercept form is written in the form y = mx + b
Where m is the slope and b is the y intercept. 
The reason why it’s called slope intercept form is because it’s very easy to see the slope (m) and the y intercept (b).

To calculate the slope intercept form, we just plug in some values for x.

Say we have this equation: y = 2x + 3
We see that the slope is 2 and the y intercept is 3.

Plug in some values for x. I’ll do 0.

y = 2(0) + 3
The 2 cancels out and we are left 3!

y = 3

We see when x is equal to 0, we get the y intercept.

So, we have the point (0,3). We need at least two points in order to graph a line.

Let’s plug in another value. Let’s do 1.

y = 2(1) + 3

y = 2 + 3

y = 5

We now have the points (0,3) and (1,5). Just run a line through it to graph it.

Here is a picture I put below to help you.

Sorry if the line isn’t exactly straight. It was kinda of hard to draw it.

That line represents the formula y = 2x + 3

If you need anymore help with the slope intercept form or any other problems, private message me the link to your question and to the best of my abilities I will try to answer it.