I realized there were non numbers in it without an x and I got lost!

I don't understand what "non-numbers in it without an x" means.

When I try to find the Yint its equal to 0

Yep.

I don't know how to go about finding the x intercept.

To find $x$-intercepts, you are looking for when $y=0$. That is, set the equation equal to 0 and then solve for $x$. In this case, you can find one of the $x$-intercepts easily by factoring out $x^3$. However, the remaining quadratic doesn't factor, so don't bother. There are two other $x$-intercepts, but you need the quadratic formula to find them. Feel free to find them, but it isn't necessary to get the overall shape of the graph.

Next, do the first and second derivative stuff we've been doing on the number lines.