The Vertex, a point on the parabola, is exactly half way between the focus and the directrix. These three features, focus, directrixm and vertex, should be sufficient to orient your parabola.
In particular, "y = something" as the directrix suggests the standard form you have written. If it is "x = something", you must switch it around a bit. There is not just one standard form for a parabola.
"I'm not quite sure how I should go about doing it" -- Give it a try after locating the vertex.