well for starters, by looking at the function it is going to be a parabula, and since the x is negative it is going to be facing downwards.
to start off graphing it, you can either do it by a graphing calculator or using a table of values, create a T table with a list of x values, and solve for their y values by plugging them into the equation
x f(x) y point
-2 -(-2^4)+3 -13 (-2,-13)
-1 -(-1^4)+3 2 (-1.2)
0 -(0^4)+3 3 (0,3)
1 -(1^4)+3 2 (1,2)
plot those points and graph it, note you can have more points if you need, you only need enough to get a general look on how the graph is going to look.